I chose to use the event as an opportunity to try out developing in MonoGame using Xamarin Studio. I chose a Monogame OpenGL app and as I worked on creating the game I discovered that this target platform seems to lack a few features. The biggest missing feature for OpenGL apps is the ability to load compressed audio files.
The (nearly) finished game, called "Tash", can be downloaded using the link below:
I did not finish the game but got to the point where the castle is fully explorable and most of the powerups work. I did not have time to create some nice graphics so all the image files used are placeholders I created in about half an hour. I also didn't manage to get any sound into the game, partially due to the problem with not being able to load compressed audio. The biggest missing feature is the ability to win the game and escape from the castle.
I found programming in C# to be just as comfortable as I remember it. Monogame is a nice game library although I'm dubious of the level of support it currently has for the Windows Desktop Platform. As a library with the tagline "write once, play everywhere" they should get that fixed although I understand that the focus of the library is mobile game development.
Xamarin Studio as a development environment was eminently usable and didn't cause me many issues. I had a problem with some dialog boxes opening behind the main window which meant I had to kill the task on one occasion, but my files were automatically recovered, It's not quite as feature rich as Visual Studio or Eclipse but the most important things such as step by step debugging are there.
In conclusion, if I do another game jam I would like to try coding with my usual LibGDX library on Eclipse. It would be nice to make a fairly direct comparison of how productive I can be. I would expect to be much more productive with LibGDX as I've already discovered all the main gotchas and tricks for this type of game. LibGDX also gives me the option to deploy to HTML5 and play on the web which is really useful for game jams, I don't know that Monogame has the option.