I go to ACEN every year. The first day I spend most of my time in the Ballrooms and such and buy what I want to buy. The second/third day, it's all about the game room!
I bring a couple of bottles of water and play to my heart's content; I even enter a few tournaments. (I almost won too! Sons of beetchiz)
Usually I'll head back over to the ballrooms to wander/buy more stuff for a little while.