Otter is a 2d game making framework built in C# using SFML as the backbone. I built it taking a lot of inspiration from Flashpunk, Game Maker, and a couple of other things. It's totally open source and usable for making games for Windows, and eventually Mac and Linux.
I once dabbled in the world of flash animations. After creating The Possessed Mouse for an assignment in college, I submitted it to Newgrounds where, much to my surprise, it wasn't blammed instantly. It ended up getting Daily 2nd Place which isn't too shabby.