Funny, entertaining thread so far.

My story doesn't rate with a lot of these, but it might help someone identify a similar sound. I was hearing a constant tick (sounded like the bottom bracket) with every pedal revolution, but I knew I had just changed the BB not too long ago. This drove me crazy for weeks, maybe months, until one day I happened to jump on the bike with no shoes on. For some mysterious reason, the ticking wasn't there.

It turns out the heel of my sneaker was catching a piece of brake cable and snapping it back every time I pedaled "up" with my right foot. I snipped off some of this extra slack, bent it away from my pedal line, and saved a lot of money by not trying to replace the BB again.