If you like to watch computer-controlled 2d fighting characters with actual decent AI (most of the time) squaring off against each other, check out http://www.saltybet.com/ .
There are over 5000 characters in the database, and it runs 24 hours a day. The matches can get really amusing sometimes.
From a technical standpoint it doesn't seem too hard to set everything up (over time), but the concept and then the monetization of it is pretty ingenious.
I've seen Salty himself in the chat every now and then. I wonder how much time he spends working on the site vs how much he makes off of it every month.
There are over 5000 characters in the database, and it runs 24 hours a day. The matches can get really amusing sometimes.