OpenSpades!

SAY HELLO TO THE CREATIVE SHOOTER. CREATE YOUR BATTLEGROUND, DESTROY IT, THEN CREATE IT AGAIN. IT'S CONSTRUCTION, COMBAT AND CREATIVITY.

This sandbox fun-shooter allows players to create worlds and maps that they’ve always dreamed of, brick by brick. They can share these virtual playgrounds with the community and use them as the backdrop for fast-paced shooter hunts against fellow players or computerized opponents. This comic style online game is built on the ‘Unity 3D’ engine and will be playable directly in a web browser. The ‘sandbox’ mode, in which players use simple building blocks to construct complex environments, can be played on social networks and mobile devices such as smartphones and tablets. Brick-Force is being developed by Korean game developer EXE Games as a co-production with Infernum. Beta and launch of the free-to-play title in Europe and North America are planned for spring 2012. »

The website linked is not real page, just moddb page. Wikipedia says all official sites have been closed.This program is now available online for free at abandonia.com.

tOpenSpadongs (or tspd) is a client for the beta version of the game Ace of Spades. It's forked from yvt's OpenSpades. It tries to focus on smooth, enjoyable competitive gameplay above all else.