Halloween? I haven't dressed up in ages, although here's what I was supposed to be the last few years:
Two years ago, I was supposed to dress up as a mariachi performer, with a suit, sombrero, and poncho [and trumpet, obviously], to perform at the high school football game on Halloween. This performance was cancelled when one of the members of the band died of a brain hemhorage -- and, understandably, dressing up in comtusmes right after someone dies is rather disrepectful. We did a tribute concert instead.
Last year, I was going to dress up as Matthew Lesko (You know, that guy with the ? suit who runs around screaming about free money in an annoying voice?) -- I had the impression down and everything, but I never got around to making the costume.
Couple people at my high school dressed up as Mario and Luigi for spirit week last year.
As for this year, I highly doubt I'll dress up, but if I do, I think I'll go for the Canadian Mounted Guard look (I have the hat already, I just need to find something that sort of looks like the uniform... our high school's old marching band uniform look a lot like it, but I don't think I can get one of those.) -- or, alternatively, I can do Indiana Jones. (Although my sideburns make that a bit hard to pull off. Bah.)
~I.S.~