We had a discount voucher for CSI. You can find them on-line or in publications in your hotel room or in a taxi. They seem to limit the number of people that go in, but it still makes sense to go in the morning or early evening so you don't have to stumble over other tourists.
You start by watching a brief show featuring the stars of CSI Vegas, and then you examine a crime scene and take notes. Then you go to various stations where you go over the evidence and learn what it means. You don't have to go in any particular order. It's all very modern and high-tech feeling.
You finish by going to a computer and figuring out the results. Then they pose you in front of a camera wearing CSI caps and vests and fake pistols with baton and cuffs. Then they try to get you to buy the photos. You finish by filling out your forms so they can print out a diploma you can buy or get it on-line for free (which hasn't happened yet). The whole thing takes over an hour and you end up in the CSI store so you can buy stuff.
I had a good time.