well...there are many....
we were in bio class....my teacher asked us whats formed after krebs cycle....I with utter confidence shouted LACTIC ACID!!! (its after fermentation).....my teacher smiled and suddenly i realized
ooopppsssiiieee....it should be ethyl alcohol.......and i was juzzzzzzz....z.z.z.z..z.z
and just yesterday i called my bestie....her bro picked up call...and i talked him saying him auntie and later he said...m not auntie...m deepak...i was sooooo embarrassed that i just LOL'd :P