I've spent a lot of the day configuring and generally playing with the new hardware I purchased to get my main Linux desktop system going again. One of those pieces of new hardware is an NVIDIA card, and NVIDIA, in particular does a good going of supporting OpenGL under Linux for their graphics cards. OpenGL is a graphics rendering standard that makes it easy to use the acceleration features of some of the nicer graphics cards, and once I got OpenGL working, I started looking for applications for Linux that would make good use of that standard.
Once such application is Stellarium. If you have any interest, at all, in star gazing, Stellarium is quite nice, and it does have Windows and Mac-OSX versions, in addition to the Linux version I'm playing with. In particular, dr_nebula, you should check it out.