I never buy something unless I'm 100% sure it's not fake. It was a company that had done this 3 times before, and nobody has ever complained.
There were a few games that I REALLY wanted, like cogs or VVVVVV, others I didn't really bother, like one called steel storm or hammer fight, but my favorite was the subscription to play minecraft for two weeks, after that, you have the game, but are not registered, so that was a plus. Could still use multiplayer anyway.
The original pack included like 7 games, but there was a promotion. when I got back from school, I got an email that all customers that bought before a certain date got the humble bundle indie pack 2. Guess what, I got all those games, then came ANOTHER promotion, where a friend told me that they added another game, which I think was atom zombie basher.
Here's the page:
http://www.humblebundle.com/