I just clicked monitor and changed it to 1 day to see if Steam downloaded anything during the past day, and 'Half-Life 2 Movies' Showed up for a few seconds then disapeared. I don't think this was a movie download, but I believe some kind of update for whatever plays the movies in Steam itself. Because it was very small. Maybe it was just a bug, but still thought I'd post this, incase it showed up for anyone else.