I have been able to get Agar apps to run in an X environment, but not when they run on a tty, whether or not the X Server is running. Several SDL langauge sites claim Linux can run SDL apps with frame buffering. I have a big project in mind that needs to be launched from a console with no Window Manager running.
Many SDL people have been friendly and offered lot's of advice, but the one's I talked to are not using Ubuntu.
Testing so far...
Agar apps won't launch from tty.
Mplayer from the repoes which supports several avenues of direct fb doesn't display properly.
VisualBoyAdvance from the repoes also will not work properly with ROM's.