Jagex announces a free weekend in Ace of Spades, their voxel graphics multiplayer shooter, which can be played on Steam gratis between now and Sunday afternoon. The game is also on sale during that time for 50% off. Here's word:

Combine construction, combat and creativity to take out the enemy in an entirely destructible world this weekend! Ace of Spades will also be available half the normal price on Steam until Monday 17:00 GMT, so it’s the perfect time to experience Ace of Spades’ unique multiplayer mayhem for yourself.

Ace of Spades has proved hugely popular since it’s launch, firmly cemented itself as one of the most popular Steam titles, peaking at #1 on the Steam charts and has consistently featured in the global top 10 list for games under £7 since December last year.