Visited my brother this weekend and we played some random Tower Defense games for fun - and I had a lot of ideas for the game and knew that Microsofts game platform XNA was supposed to be really good.
I spent a few hours remembering how vectors worked, making a small game was an absolute breeze. The result so far is:
The monsters walk the path and you can place 3 different kinds of towers that will attempt to eliminate them. I'm currently working on getting some level balance, as my current 5 levels are way too easy. Pondering putting it up on codeplex or some other site when it is more complete.
Stay tuned for more.