The importance of a good warmup before games cannot be overemphasized in my opinion. Often times when we go to tournaments, there is such little time in between games, but it is still important to get that stretch in before game time. Here is a nice concise 1 minute video of Alan Stein running the DeMatha through a quick warmup in a hallway before game time:

I've broken it down from the video:
- single leg swings against the wall
- can openers against the wall
- sprint to chop feet to sprint to chop feet...
- partner cross arm to sit pulls
- defensive slides
- single leg twist hops
- static backward lunge
- single leg box hops
- static squats
- static split squat
- static backward side turn lunge
- static forward lunge body turn
- two foot side hops

For more great ideas, check out Alan Stein's DeMatha All-Access DVD Set.