Dungeon Defenders, which launched its Mac version and latest expansion today, will be free to play on Steam until Sunday at 1PM Pacific. The game itself will also go on sale this weekend for 50 percent off ($7.50) until Monday, March 19, at 10AM Pacific.

If you've yet to check out this addictive tower defense action game, now's the time! All you need is some motivation and a computer that connects to the internet, and we just took care of the first part for you.