Bring gently used or new game(s) to trade. For example if you bring 3 games you will get 3 white and 3 blue tickets. You write your name on all 6. The white will be taped to the games you bring, the blue go in a bowl to be drawn from later. Since you brought 3 games, you will get the draw 3 blue tickets. You MUST put the blue tickets on games with a DIFFERENT name on the white tickets. This will make sure everyone gets something different to take home.
The games should have a $20-$40 retail value. This for FUN ONLY. If you worry about coming home with a lower value item, maybe you should not attend.