Seems like I usually summarize a few things the night before...
bring plenty of adhesive
bring your camera
bring any drinks you want besides coffee, water or cider
be sure you have all your swaps, shoebox pieces, etc.
pack your basic stamping supplies -- tape, paper trimmer, scissors, bone folder, etc.
gift swap (wrapped) if you're participating
cards/fronts to donate to From Our Hearts (see Arlene's post #285)
If I forgot something, I'm sure someone will chime in.
I'll check in early in the morning before I leave the house so you can ask any last minute questions here.