I’ve just spent the last four hours playing a tower defense game, this one’s free and here’s the link: Play Warzone – Tower Defence.net, for your tower defence games
I just find them very very addictive. I’m tempted to take a quick break from the platform game engine and make a quick one myself. It’s always good to have side projects and I think this would be a good one, they’d be some nice programming functions in there too, like A* pathfinding and a lot of code using types for the different towers and enemies.
Another one I really like is Master of Defense, http://www.master-of-defense.com/ this one costsjust over $20 but is well worth it.
The only real problem I have with them is the amount of time they take up. Before you know it, it’s dark outside and you’ve been playing all afternoon. It’s like playing World of Warcraft all over again!