Last Remaining is a 3D FPS RPG in the same vein as Deus Ex. The idea is to have an engrossing storyline where the player must take whatever action is necessary to get to the bottom of the mystery. The game is written in Java with JMonkeyEngine and first version was uploaded yesterday. Intriguing and definitely one to watch. :-)
The author is the same guy behind Passenger and Nuclear Graveyard, and has a devblog on his various game programming endeavours.
A previous release of Nuclear Graveyard had managed to become corrupted when uploaded, a fact which - much to the author's dismay - nobody reported for nearly 2 months despite over 100 downloads. Anyway, if you were one of those people who downloaded the game and (benefit of the doubt) was unable to get it working then now would be a good time to try again!
He is also moving Passenger from JOGL to jMonkeyEngine (which uses JOGL) which should make subsequent development of the game easier. Anybody who things Java is slow and rubbish for games may want to check out the jME showcase page.
It turns out that at least one of the games on that showcase page is open source! Air Carrier looks like a splendid 3D aerial combat game. It aims to support single and multiplayer, with gameplay based around plane to plane dogfighting, and strategic use of airborne carriers.
Another notable open source project using jME is Java Classic RPG - the development of which is continuing at a nice pace.
All of these games mentioned today should support all major operating systems (at least Lin, Mac, Win plus anything else supported by JOGL) as they are written in Java - and Java is portable, right? ;-)
There is another good article over at Liberty Gaming that discusses stratagies for expanding Free gaming. He mentions Project Open which I need to really follow through on. Also I hope FG and the FG forums somewhat contribute towards making open source games more accessible, that's the intention anyhow.
I did have something else to mention but I'll save it for tomorrow.