I think this game is quite old but it's one of my favorites, I bet non of you that are reading this have tried it, but you should.
It's basically a defense game were you prevent monsters from running into your house/shelter.
It is very addicting, so if you've got a lot to do, you might not want to try it ;).
Oh and this blog has been growing crazy! I had like 5 followers the first day :). Glad that you enjoy this!