These are a few of my current favorite programmer/nerdy type projects on the web-
ReactOS – I’ve been watching this one a long time and it seems to be building steam. This is a free/open source clone of Windows… While still in alpha stage, and crashes are frequent, it is truly amazing how much windows functionality is working. Even Firefox 2.0 runs in it. I’ve been contributing some bug reports and compatibility report, and hope to get deeper involved in the future.
Cosmos – A .Net based OS… ok that’s a bit confusing, but basically you write .Net code and this project is able to compile the .Net into direct assembly language. Also a bit early, but also progressing nicely. I’m envisioning using this on some small and/or embedded systems in the future.
Phalanger – This is an awesome project which compiles PHP code into CLR… so you can run all those php apps in an IIS/.Net environment, and even develop in visual studio. Unfortunately it has gone a bit stale, the rumor I heard is one of the leads was hired by MS and doesnt have the time to put into the project any longer. I’m hoping the best for the project.