As quoted by James Cottee from www.games.on.net at March 19, 2011, 9:53 AM:


"For this weekend only, Monday Night Combat is free to play via the Steam digital download service.

The promotion is running through to 1pm Sunday, Pacific Time (ie. 7am Monday Sydney time). Those who take a liking to this whimsical class-based shooter during this time can buy it for just US$9.99, a saving of 33% off the normal price."

Source: http://games.on.net/article/11935/Monday_Night_Combat_Free_Weekend_Now_Underway_on_Steam

P.S. Thank You people of Uber Entertainment for this exciting promotion!