TellTale games, the makers of CSI: Hard Evidence and Sam & Max Episodes, have released a CSI: Hard Evidence demo for the PC on their website. Heads up though: the game is rated M for Mature, but you should already be used to the violence if you have watched CSI before. The game only allows you to play through the first case though, but it should be enough to convince you to buy or not buy the game.
You can download the demo here.
If you are not a CSI fan, you probably won’t find this game very fun. Sorry.