A thread called "Post your Open Source Game" on the gamedev subreddit let me discover some new and old projects.
Here are three of them:
A hyperactively fast jump and run with chainsaws: Zolo.
An OGRE-based real time strategy with vegetables and taco: Food Fight.
An "adventure game in a post-soviet environment": GameLV.
Here are three of them:
Zolo
Food Fight
GameLV