VLC Media Playerhttp://www.videolan.org/vlc/index.html
VLC is crap.You might as well get an flv to avi converter.
I don't know about you guys, but when I recorded something on blockland and played it on VLC, it was distorted hue angle sideways stuff like someone stretched an old movie film tape up on one side and down on the other
Actually, it's pretty good aside from a few glitches.
media player classic does everything better.