I recently heard about Tesseract, which from what I heard is a modification of Sauerbraten that uses all dynamic lights and directional model lighting. However, I also heard that it requires a really good computer and it has trouble rendering maps with a lot of lights, and since the rendering approaches are so different maps with lots of lights will simply be unplayable.
Here's an article: http://freegamer.blogspot.com/2012/04/tesseract-cube2-next-gend.html
So what I'm wondering is, what's the future of Tesseract? I really want to see this mod go places, but I don't want to have to give up all the graphically-intensive maps.
Also, even though I'm not a huge fan of Minecraft, this mod pretty much paves the way for a free, open-souce Minecraft with graphics a million times better than the original. An even cooler idea might be to somehow combine Sauer with Minecraft's buildability, so you can have deathmatches with destructible environments where you can build up defenses. (It might not even be as far-fetched as it sounds, there's already a Minecraft map importer on the Cubic Matter forums.)