Odd traffic spike

My website hits went through the roof on Tuesday:

Odd Spike

I have no idea why this happened. Technorati isn’t suggesting I was linked to by anybody with major traffic, all the hits were to the front page rather than any specific article, and I didn’t actually post anything during the day. Given that hits on my feed went up by a similar percentage I’m guessing it was some kind of insane bot, although the disparity between unique and total visitors doesn’t really tie up with that. Dunno.