Recently I've been looking into different game prototyping environments for quick game development. Prototyping in game development is basically creating a sample of how the game works, and focuses on getting a working sample up and running as quickly and simply as possible.
I started looking a C# and XNA. C# is a great language for throwing something together quickly but C# and XNA isn't as portable as I'd like. From there I started checking out Python and Pygame and found it to be a pretty viable option for throwing a game together. Not wanting to settle I kept looking a bit and was recommended to check out Lua and Love2D. I hadn't played much with Lua and found it to be pretty neat but not as popular as Lua. This time around I checked out Love2D as well and discovered that it was even quicker to throw a small game together with it also looks pretty popular on forums discussing 2D game prototyping. So I'll see where it goes.
A couple links I found that I'll post here for others going the same route:
http://gamedev.stackexchange.com/questions/854/what-are-good-games-to-earn-your-wings-with - some ideas of types of games to create while starting your game development journey
http://www.ludumdare.com/compo/tools/ - popular tools used by Ludum Dare participants - more on this later
http://gloryfish.org/ - a couple videos showing the making of some games