**UPDATED 1/13/06: FIXED URL WITH NEW LINK FROM ALAN.
A while back I posted about a J# version of Peter Walser's original IDX3D engine. I recently received an email from Alan Simes reporting that he had done another port, this time to 100% C#. Check it out here. The screenshot below is one I created using Alan's port, and I must say it's VERY responsive even on my laptop. It spins around quite nicely which is both a testament to Peter Walser and to Alan. It's really neat watching these things evolve from one generation to another via ports and such. :-)
Another cool part about this is that Alan built it using the beta of Visual C# 2005, so if you wanted to compile this for yourself and you don't have Visual Studio you can download Visual C# Express edition from here.