Unless you want to be stuck in one out of the way place forget the tripod.
A tripod also means you can offer something completely different to the millions of P&S (and possibly other cameras) that will be there.
ie. not just portraits and lots of flash.
My sister-in-law is having a 21st birthday party and has asked me to taking picture throughout the night.
I have a flash gun, tripod and a remote, any thing else I need or any tips anyone has would be great,.
Cheers
possibly a camera
a 6x4 piece of photo paper or something folded in two and an elastic band
I think the results are better than some pro defusers
..or buy a defuser