Go Home Dinosaurs! is the most unique Tower Defense game I've ever played.
You play as gophers, protecting your barbecue from dinosaurs. Your towers are shaped like Tetris shapes and your strategy doesn't just rely on putting out as many towers as possible.
Your strategy has to revolve around placing your towers where they will fit, where they can do the most damage and where it won't block you from attacking the dinosaurs yourself.
If you're a fan of tower defense, gophers, steak or dinosaurs, do not pass this game up.