[enervate]

I read this word before I ever heard it. It looked like Quintuple to me, so that's how I pronounced it.

[mykeliu]

I've heard "quintuple" both ways so after reading your comment, I still don't know how you specifically pronounce "tuple" :P

[nostrademons]

I've also heard "quintuple" pronounced "quin-TUH-ple" when used as a verb and "quin-TOO-ple" when used as a noun or adjective, so there's a part-of-speech distinction as well...

[wjdp]

Being mostly self taught I had a few of these. First couple of months working with other developers one would come up every week or so. Luckily not very embarrassing. The new juniors have a few too!