The last couple of times that I've hung out with Krishan, he told the same joke. Here it is:
Have you heard the joke about the Jonestown Massacre?
I'd tell it to you, but the punchline is too long.
I was confused both times, because I didn't really know anything about the Jonestown Massacre... I forgot about it until I went to the library earlier this week to get some more music. I go there pretty regularly on my dinner breaks to borrow stuff to listen to at work. While I was browsing through their CDs, I stumbled upon a band named The Brian Jonestown Massacre! I always act on weird little coincidences like this, so I grabbed it. After I got back to work, I listened to it while reading the Wikipedia entry for Jonestown. That was an odd experience: ready about the Jonestown Massacre while listening to The Brian Jonestown Massacre.
It's a bad joke... but at least I get it now.