2004 Great Lakes Regional would probably count, if it hadn't happened at the end of what turned out to be the TechnoKats' final match.
http://www.chiefdelphi.com/media/photos/16516
The "Year of Fried Sidecars" at 2011 Boilermaker gets my vote, but that's mostly because replacing the Digital Sidecar on that robot 1) involved removing and replacing a lot of wires with almost no room underneath a bizarre assembly of chains and sprockets, and 2) had to be done several times during the weekend.