What was the worst bug you've ever solved ?
tlb: Runaway robots at Anybots have caused:  - 2 holes in drywall
  - 1 bent bookshelf
  - 1 dent in concrete floor
  - 1 frightened Jessica
  - http://www.youtube.com/watch?v=qkenIInV9rI

The last one was fun because I have logs showing packets from the PC/104 computer stack (running FreeBSD) connected to the robot while it was in midair.