Also see http://youarenotsosmart.com/2011/08/21/the-illusion-of-asymm...
Doing it in a comedic fashion doesn't help, it's just bullying.
Peer: Synchronized? Me: I'm sorry, you've crossed over into an area that I expect you to understand on your own.
That kind of room-silencing confrontation makes you seem like way more of an asshole than answering their question but with a raised eyebrow or feigned surprise.
In a meeting with a peer (rather than a training course/academy situation) you'd presumably tell them that that's fairly basic stuff that you don't want to derail a meeting with, and that you'd point them at some resources later.
That's not how I'd mean it at all. Maybe I'm overanalyzing our folkways but in general it seems to be more polite to communicate something unpleasant in a way which the other person can pretend to not have noticed. Twitching your nose when you know they're looking is more polite than saying "dude you've got BO." It allows you to gloss over the unpleasantness and continue the conversation.
I've been this guy. There was a good long while when I would just bob my head through stuff that I didn't understand at all because I was afraid of being humiliated in public, and then go back to my desk and spend hours trying to figure out what I was supposed to be doing. I was lucky enough, a few years back, to run into a very understanding mentor who put some effort into deprogramming me and making it clear that it was okay to ask stupid questions.
Making people feel small for being ignorant isn't just rude, it actively destroys productivity.
If you continue to find them asking questions that suggest they spent most of their development career under a rock, present those concerns to your employer. Help them make a decision whether or not this person is able to perform at the level they need to.
If it's a one-off thing though, and they seem otherwise fairly competent, then it's a good thing you didn't act like a jerk because now the person doesn't resent you, and they won't have to ask you what Lisp is again.
Source: I've worked with several developers at a level much lower than I expected, this was in one case how I wished I had reacted, and in two other cases how I did and it worked out well.
If they point me in the direction of some resources or help me learn it I'm going to respect them more because it makes it clear they care about their craft. They don't feel the need to feel superior, they'd rather have a peer on their level.
My point really is just that different people are motivated in different ways and what may motivate you has the opposite effect on others.
Clocks for one, file content replication for another, version numbers of software a third.
I have more of a problem with the people who think they know something and reject it out of hand (typical executive attitude) than those who admit they don't. You and I, as well, once did not know what Lisp is.