I can wiggle my ears too. But so can a lot of people. What can you do?
I have a double-jointed left thumb which I can do strange things with. With my thumb alone, I can make people say things like “Ewww, that’s not normal!”.
I can touch my nose with my tongue.
I can touch my nose with my tongue, too.
I can crack both my wrists over and over again.
I’m really good at falling down stairs, and off bicycles.
I can clap with one hand, with both hands.
No, that didn’t come out right. What I meant to say is, I can clap with one hand, with my right hand and with my left hand.
OK…I mean, I can clap with one hand, using my right hand. Then, after a suitable span of time, do the same Zen-koanastic thing with my left hand. They would have loved me in feudal monastic Japan.
Hey, we share a talent!
I can make my mind go blank. Um…
No, wait! I can make my right eye do that inward thingy. (I was born that way and treated, but still, I can do it.)
I can pass an 8 pound mass of human flesh through my vagina.
I can use organs in my face to retrieve visual imformation about the world around me.
I am pigeon-toed, so I can bend my legs weird. Imagine folding your legs straight back (with the back of your shins touching the back of your thighs). Know what I mean? Well, my bones are weird, so when I do that, my legs go slightly off to the side. It looks very weird, like I just broke my legs.
Also, do you remember the “butterfly” in gym class? Hard to describe if you don’t know what it is. Well, I can actually pull my legs so far in that I can sit on my feet. Also a perk (aka curse) of being pigeon-toed.
I can do the crosswords while taking a dump. Sometimes I use a pen or pencil.
Ah yes, but in which direction? 
I can wiggle my eyeballs. Sometimes they do it independently of me trying to. My eyes have a mind of their own…
-foxy
My right thumb is double-jointed, and I can make it bend in a way that appears most unnatural. I’ve freaked out a couple of people with it when I was in junior high.
I have the ability to sleep through virtually any kind of loud noise. Granted, I’m deaf and I don’t sleep with my hearing aids on, but I think that still counts.
I can do Francesca’s eye thing too! And I can bend my little finger down so the tip is touching the palm of my hand without moving the finger next to it.
Aww, c’mon that doesn’t count! 
Both of my wrists seem to be unnaturally loose. Either of them will bend forward to a rather impressive degree. A lot of people can do this until their thumbs touch their forearms. Me, I can do it until my thumbs go past my forearms. This involves bending my wrists well beyond 90 degrees forward.
At the same time, if you look on the back of the joint, a sort of ‘gap’ appears. Many people find this disgusting, and I use that to my full advantage. 
I can curl my tongue into three separate curls, resulting in a clover-like shape. I can also touch my nose with my tongue.
(Side note: Once I preceded telling a girl about these abilities with “Yeah, I can do some weird stuff with my tongue…” and she interuppted with “I bet you can…” Whoops, not what I meant.)
I can raise one eyebrow at a time like that wrestler guy–is that the Rock? I don’t follow wrestling enough to know. But I don’t have to “furrow” one eybrow to raise the other independently. I can do it straight from a normal, relaxed position.
My feet are so flat that while standing on linoleum I can make both of my feet make suction cup sounds. Which makes for very intersting after dinner conversation.
I can lick my elbow.