For me, there are many words that just make me laugh every time I hear them. Doesn’t matter when or where. I could be at my mother’s funeral, and if some said the words:
Fine Young Cannibals
I would manage to laugh. Every time. Any mention of “Chuck Woolery”, or “pull my finger”, I just can’t NOT laugh.
Anybody else?
Sala, can’t you count?!? I said NO camels! That’s FIVE camels!
Bondo.
Especially if pronounced
BonnnnnNNNNNNDDDDDDooooooo! like a WWF fight announcer.
Go figure!
VB
I’ve performed a complete diagnosis of your car. It’s broken.
Ricola (sp?). And what’s worse, sometimes I pronouce my son’s name (Nicholas) all drawn-out just like in the commercial.
Neee-coooo-laaasss
Neee-coooo-laaaass
One day somebody is going to call child welfare on me!
Sometimes “Rick Springfield” will make me laugh, but as for words (and not people) supercilious (meaning haughty) makes me die laughing everytime I hear it.
“I need the biggest seed bell you have. . . no, that’s too big.”–Hans Moleman
Okay, it’s not a word, but that “Woohoohooo!” sound that Goofy makes in all the Sport Goofy cartoons as he goes off the ski jump or whatever, makes me laugh my ass off, every time. 
Jodi
Fiat Justitia
“Naval intelligence” always gives me a chuckle!
Rich “G7SUBS”
Ever since I heard it for the first time (in Gilbert and Sullivan’s The Mikado), I laugh when I hear the word “snickersnee.” I’m not going to define it, look it up if you have to, because I had to and I’ll be g***amned if I make life easy for you guys.
My friend Bryan has gotten in the habit of saying “Ball sweat” as an exclamation. It just cracks me up everytime he does that.
“Titilate” makes me smirk too.
You say “cheesy” like that’s a BAD thing.
Okay, there are two. Well, one is a word, the other is a phrase.
When I was a kid and my mom would lecture me, she had her certain “Momisms” that she’d use. One she used, when I had done something especially stupid, would be, “I cannot believe that you had the GALL to…”
Everytime someone uses that word (which, thank goodness is not often), I crack up. One time, I actually laughed during the lecture. She said, “What do you think is so funny?” I said, “Mom, what the heck is gall? And why shouldn’t I have any of it?” She cracked up, too.
The phrase that cracks me up is “This place looks like a bomb struck it.” A friend’s mother always used this one. Until she was twelve, my friend’s sister couln’t figure out what a “bomstrucket” was. Only that it apparently bore an eerie resemblance to her bedroom.
Maybe you had to be there.
I never hate myself in the morning. I sleep till noon.
–Sig line courtesy of Wally
Dichrotic Notch.
Dichrotic Notch? That doesn’t make me laugh it makes me itch.
Kumquats (the plural is funnier for some reason)
paradigm (not so much the word, more the fact that managers who use it don’t have a clue what it means)
The Scots - never trust a race whose national dress includes a concealed knife.
D’oh, strumpet, and heinous all make me laugh. Go figure.
Brouhaha. I can’t believe anyone really says that word out loud.
Catrandom
shitballs makes me laugh. especially “holy shitballs”. hehe, im laughing right now!
“I am so smart, I am so smart, s-m-r-t, i mean s-m-a-r-t”
turd! that word gets me everytime
and my SOs friends mom says “nimnose” I just love that term
Tee-hee…this whole thread is making me laugh!
‘Lake Titicaca’(sp?) always makes me giggle.
Rose
I told you not to be stupid, you moron.
I forgot one…
My mom has a made-up word for the dog bombs in the back yard: Scoop-doody.
She ususally uses it as a noun, as in ‘don’t step in the scoop-doody’ or ‘look at all the scoop-doody’.
Cracks me up every time.
Rose
silly monkey. that to me is just goofy.
Lake Titicaca, of course.
Also, “titmouse” makes me giggle
The first word that comes to mind is “succotash” (tip of the hat to Carlin.) But jodih’s post about the Goofy sound reminded me that I scream with laughter whenever Tom gets, say, struck on the head in a Tom and Jerry cartoon and lets loose with an earsplitting “AAAAAAAAAAAAAAAAAAAAAAAAAHHHHHHHHHHH!” or “Ow OOOOOOH! HOO HOO HOO HOO!” (doesn’t translate well into print, sorry.)
“Satan – I’ve had enough of your two cents!” – The hilarious Federalist