I think my favorite still remains a guild-run 10-man Naxx back in pre-3.2.
We're just mowing stuff down best we can. nuke Spider Wing like we always do. (hence why I never go back to Naxx unless it's for a VERY good reason. so sick of seeing Maexxna and her poisons.) Then we move onto another wing and so-forth...
Finally we're at the pipe leading to Gluth, and after summoning the few people who were goofy or laggy enough to fall off the pipe, the RL asks who's got the strongest kiting experience to kite the zombie-chow.
I kid you not here, folks. Probably sixty full seconds of dead silence before BOTH our hunters go 'uhhhh...I...never really kited.' or 'It's...been a REALLY long time since I've kited.'
RL goes to the mages we had 'you guys any better?'
'um...the hell is kiting?'
Yeah...we got him down, but the hunters at least I would have thought would have been acquainted with the concept of kiting. Same thing goes for Interrupts. last time I did KT, I think I was the only one interrupting Frostbolts. Not like the healers couldn't handle it but still.
Sad thing is that at one point I pondered putting together a night specifically for refreshing people on these skills. I was pretty much given flak and talked out of it because 'there's not really a need for it these days.'
"I don't have a dream, so I protect the dreams of others."~Inui Takumi