So I'm not the only one to work on cross platform .NET applocations (how come I'm not really surprised..?) The Banshee Project is a cross-platform multi media player based on .NET and Mono. Though my only experience with the Banshee player is not positive ( It could not play MP3 without hickups on my EEEPC ) it is a great project to show the power of cross platform development. And I'm sure one of these 95 developeres working on it will eventually solve the EEEPC problem.
Banshee creator Aaron Bockover talks about it in a recent Hanselminutes Podcast. Both the show and the shownotes mention that it will run on Windows, but I actually could not find it on the Banshee homepage. On his Blog he mentions working on it, (despite of his aversion to Windows programming) but the status of it is not really obvious.