Last week a new build of Sauerbraten was released. Sauerbraten 2006-09-12 notes state:

Notes: eyecandylicious water, and lots more!
Well, what is this "eyecandylicious" water? Below are a few shots for demonstration purposes. The water reflection and refraction improvements in this release are quite interesting, and poses the question what will be next for this open-source title. (The water is much more interesting when you see it moving rather than a still snapshot) Sauerbraten can be downloaded @

For reference, the system used where the screenshots were captured was running an ATI Radeon graphics card with the 8.28.8 fglrx drivers on Fedora Core 6 (Test 3).