With the recent release of Wesnoth 1.2, the open-source strategy game, the game's developmet never seems to stop. It's so popular, and it's addictive to play.
These days, anybody without internet access is considered to be "living in the dark ages". And with the ever-growing popularity of social networking services such as MSN, it beomes increasingly important to provide multiplayer support in a game written, be it commercial or open-source. Wesnoth has a good server with lots of games being hosted, so people enjoy not only playing the game, but socializing while doing so.
But what about the actual game? Well, it's fantasy, which makes it more fun (just take Harry Potter or Lord of the Rings as an example), but it also has very good graphics. Although they're not 3D, they're very polished and add good eye candy when battling some vicious enemy. The graphics and the sound help contribute to this game's wonderful polished feel. That, and the fact that there's lots of pre-made tutorials, and even more user-created ones available for download.
The reason that you don't see a lot of this level of quality games in open source is that the vast majority of the developers want to create 3D FPS games and the like. And since they're not getting paid, they don't have the motivation nor the time to add all the special features that make playing a game like Wesnoth such an experience. Remember that saying, "don't bite off more than you can chew"? Well, this cliche actually has some truth to it. It's highly unlikely that if the Wesnoth crew started this in 3D that they would have had such success in creating it.
Creating something simple gives enough time to work on special details. It also allows you to actually finish, and not get stuck like the huge number of projects at sourceforge unfortunately crash.
I know, you want to create a FPS, and not some stupid 2D game. But 2D games are still fun, and the fact that a well-polished game will draw far more players than a half-finished 3D first person is something you may want to consider when drawing up your game's design document.
So I tip my hat to the Wesnoth developers. Because they've done a good job, and they've restrained themselves from tackling something far too big for themselves. Let this be an example to all.