Had a formal corporate in-person interview last month at flight department HQ (after a prior informal interview with the CP).
Within the first 3 minutes I got slightly animated while answering a question and while "talking with my hands" I managed to snag the wireless computer mouse on the table.
The mouse flew up in the air, landed squarely in the middle of the table, and broke open sending batteries and plastic parts flying towards the five person interview board. At least it broke the ice when one of the interviewers exclaimed, "That was a Test!"
It unnerved me for the rest of the interview however. Moral-just be yourself and if it's a good fit it will work out.