i've been to a couple of these things now and what you're going to find is, like John said, you don't have to worry too much with the guys that are going to be there but everyone should bring a minimum amount of stuff.
I don't have spare axle shafts (yet), but I consider the minimums to be fluids, u-joints & straps, spare, hi-lift, tow strap (no chain and no metal hooks) any spare parts you have and can fit, tools (I have a 3/8 rachet set with extensions and wobbles, assorted screwdrivers, metric and inch wrenches, tork sockets and drivers, a small sledge, and all my Jeep-specific tools), TOILET PAPER, bug juice, trash bags, tire pressure gage, bungee cords...
that's about all I can think of off the top of my head. Oh, you need to be sure that everything you have in the Jeep on the trail is secured. Any tool boxes or containers have to be at least strapped in.
Guess that's all I can contribute. This list just makes me realize how much work I have to do to get ready tomorrow night... sheesh
