OK - here’s another one of mine. I love eating chocolate covered espresso beans
Whee!
I tried chewing a toothpick before. I was at a nice restaurant and extremely bored. Halfway through I started spitting out toothpick slivers onto the lovely, rich, maroon carpeting when no one was looking. Shocking thing is I actually got away with it.
After that, i used to eat styrafoam cups. I never actually ate any of it, but it ripped so easily that I would take huge chunks out of it once I was finished drinking. My friends always made fun of me when they saw my hole-ridden cups filled with tooth marks.
Another pen clicker here. However, I only click it when someone is talking to me. It gets worse. While the person is talking, I don’t even look at them. Rather I intently study the pen while I click it. I’m sure I’ve highly insulted a couple of people by now.
Oh yeah, and my teeth are fine.
I run my fingers thru my hair just looking for snarls. I pull and pull and pull. When my kids were little I would pay them to pull my hair before I went to sleep. They laugh about it now.
Oh, and sometimes I remember things I couldn’t remember “after” I’m not trying to remember them. That may or may not be habitual but I just thought about it.
And thank you Sublight . I would have been here earlier but I was stretching my string to the limit .
Something a little worse for my teeth, if I drink from a can(Which I try my hardest to refrain from doing) once its empty, I’ve just got this useless empty can, I basically dismantle the thing with my teeth, making a small hole and moving the can so that my tooth makes a cut down the can, or across it, or whatever, the end result is often several pieces of very sharp sheets of metal. Oddly enough, I’ve never cut myself doing this
Sometimes, when I get really nervous, I’ll stick my fingers under my armpits and then I’ll (sniff) SMELL 'em! Okay, maybe not quite, but I do tend to check for pit odor late in the day.
I often massage my forehead. I also have a semi-compulsive habit of rubbing my chin just to make sure I didn’t miss any spots when I shaved. I check it periodically throughout the day to find out how much hair has grown since. By the time I get home from work my chin will feel like sandpaper.
I also rub my tongue over the front of my top teeth to feel for plaque. If my teeth feel rough then I know thy need to be brushed, which of course I do every morning.
I also do the same thing with bubble wrap. I can never just lt it go without popping as many bubbles as I can.
I sometimes click pens against my teeth so I can hear the click amplified throughout my skull.
Yes, I’m weird.
My college roommate used to howl with laughter (behind my back) because I’d get up in the morning and comb my hair before going down to the shower. She thought I was primping for a stroll down a dark hall at 7:00 am! Actually I was getting rid of the snarls, which I don’t think was all that weird. Even after I told her this, she still thought I was ridiculous.
There are numerous things I do that my children think are funny enough to repeat in “can you believe my mother does this?” sessions at school. Lately they told me how weird I am because I eat fruit and various other things on the top of spinich salad (strawberries, mandarin oranges, salmon). But they’re kids so of course they think anything remotely gourmet is weird.
I’m a knuckle cracker. I can’t stop until I go through all 10 fingers at least twice. I do it constantly too. At least every 10-15 minutes. I’m surprised I don’t have Hulk sized knuckles by now. It drives my mother nuts but it serves her right since she’s the one that got me into this blasted habit. I also can’t put shoes on until I pop my toes otherwise later in the day I’ll feel the need to take my shoes off just so I can pop my toes.
I’m also a leg shaker/foot tapper. It’s a rare moment when I’m sitting perfectly still. Even at night when I go to bed I lay on my side and rock until I fall asleep.
All in all I’ll just say I’m pretty damn figidty.
Hey CrakMine!!! Ha! Now I don’t feel so weird after all! My brother does sort of the same thing, except he uses his leatherman. It’s really strange watching him. He’ll see a dead, empty, useless can and if he’s holding some sort of tool, brandishes it like a weapon and attacks the poor unsuspecting can while shouting something like:
“Die!!! You will be destroyed!!! Mwahahahahahaaaaaa!!!”
Though I’d still love to see him do it with his teeth.
I manipulate my nose.
I toss my pen. Over and over. Throw it up so that it flips end-over-end a couple of times, catch. Repeat indefinitely. I don’t even have to watch what I’m doing any more.
I seldom remember to check if the pen is on first. On bad days I’ve had ink stains all over my hand (and even my shirt).
Wow. I think I’m a composite of everyone on this thread…
I play with my beard, I check the boards first thing when I wake up, I twirl pens in classes, I flick my lighter in my pocket…
The two things I do nobody’s mentioned yet…
I clap the upper sides of my feet together when I’m laying down, and occasionally I interlock all my toes (something I thought everyone could do until recently http://boards.straightdope.com/sdmb/showthread.php?s=&threadid=199487&highlight=monkey+feet )
I also keep bottle caps or cigarettes on my ears (where old-time accountants kept pencils) when I’m drinking…
I click my teeth together in time to whatever imaginary song is playing in my head at the moment.
I simply MUST have Silly Putty or a Koosh ball in my hand whenever I’m in front of the computer. If I don’t have my Silly Putty or Koosh ball then I must have a pen cap to play with or chew on.
Add me to the list of folks who check the SDMB as part of their normal daily routine. It’s as much a part of my day as brushing my teeth!
Wow, never realized just how much of a freak I really am. Glad I’m not the only one. 
Are all of the Keynesians dead now?
I crack my knuckles constantly. Or if Im holding a pen il tap it continously off the desk or whatever when Im not actually writing.
I curl my toes under when sitting down and barefoot. It drives my mom nuts: “Straighten out your toes! That can’t be healthy!” I don’t do it consciously, it’s just one of those unconscious things.
I also play with my jewelry (usually pendant, watch and Medic-Alert bracelet). The pendant is my favorite, since I can flip it around, twirl it, dangle it, etc. This habit, by the way, is why I do not wear rings on an everyday basis. Nearly lost them too many times slipping them on and off my fingers.
My work ID card comes on this little holder that stretches out on a string and snaps back when you let go. I am ALWAYS playing with it. I swing around the card … I hold the card and swing the other end… In fact, I had to put the damn thing down just to type this. And I’m at home.
Also, and no one in the world knows about this but me, when I take a shower in the morning and I know I have to get out (but don’t want to because the warm water is so relaxing), I have to count down from five to zero. When I hit zero, I have no choice but to turn off the water. Some days that countdown is pretty slow…
Wow…I think I do just about everything here.
Just another thing to add I don’t think I’ve seen, I swing my legs (below the knee, sort of straightening them out) constantly, or I stop for a while then swing them again to crack my knees, I love the feeling though I can’t help but feel it’s not good for me.
I eat chicken wings…and LOTS of 'em.
I must eat all of the ‘drumette’ parts first.
Then I can eat the ‘two-bone’ parts.
I cannot stand to see anyone sitting on a roof/trunk/hood of a car. Drives me bonkers.
Archergal I do the exact same thing with my hair whenever it’s long enough to twist it, used to put horrible knots in it though. I found it oddly relaxing to just sorta sit there staring off into space twirling knots into my hair for five, ten minutes at a stretch. As soon as I get a haircut though the temptation is gone, very weird.
I’m a general fidgeter - like a lot of people in this thread I do the pen twirling thing, when eating out I destroy napkins by fidgeting with them while I eat. I have a pretty nice little one handed pocket knife that I’ll often flick open and close repeatedly when I’m thinking about something. Cardboard boxes aren’t safe around me, when one is sitting around I get an irrestable urge to destroy it, usually but throwing the above knife into it over and over again (which is bad because it’s not at all balanced like a thrower and I have the scars on my feet from ricohets to prove it!) or just randomly slicing into it. I dunno, there’s something oddly safisfying about cutting something with a really sharp knife. Yes I have a lot of little half faded scars on my fingers 
I’m also a pacer. When I’m on the phone I can’t sit still (cordless phones are your friends) I have to get up and move around I can’t help it. From the moment I get up to answer the phone I’ll literally start walking laps around the apartment, I don’t even realize I’m doing it really until I think to myself “Why am I in the kitchen?” I’ve walked myself into exhaustion on rare very long phone call. I also pace when I’m alone too. When I’m thinking about something, or writing, I’ll usually get up, pace around the room and err talk to myself, in order to sort out my thoughts more clearly. This usually isn’t a problem but more than once while in college I’d be working on a term paper of some sort, get up and start pacing around while sorting out a tricky paragraph, but get on a roll and speak out the paper to the end, only to completely forget what it was I was stuck on in the first place.
To make for a really fun night I’ll often end up combining several of the above habits: Pacing around the room talking to myself while playing with a pocket knife looking for boxes to destroy. I’m a freak.