Linux users can now get their hands on the latest version of FreeOrion, the turn-based space stategy project inspired by Master of Orion games, without having to compile it themselves. See this thread for details. It worked well for me, although the game is not easy to figure out and is incomplete - I couldn't work out how to do too much. However for fans of the genre the project is definitely worth following and I'm sure the FO guys would be glad of any extra help.
There's murmours over at the FreeTrain project - tangible progress on an SDL port is evident. One of the developers posted a screenshot with a basic UI much closer to the original A-Train games. Moving to SDL is the major hurdle for making FreeTrain run on Linux - currently it uses .NET and DirectX so can only be run on Windows. Forunately the project is moving towards Mono and SDL. :-)
Er, what else is happening? Not too much...
There's an opinion article on Linux Lookup discussing the problems with Linux/FOSS game development. On the face of things, the author seems to be spot on, but if you think about it properly I think he has completely missed the real problem with FOSS game development. It's not about lack of talent, artistic or otherwise. Or lack of good environments, or lack of anything for that matter. The single biggest problem with FOSS game development is the lack of consolidation. Duplicated effort, too many projects chasing similar goals, too many people solving already-solved problems. If we could harness just 25% of the wasted effort in FOSS game development we could produce some very high quality games. That has to be the community goal, to help eachother to help eachother because whilst competition is healthy, teamwork is powerful.