Hat tip to forum member TheLastProject who posted about a promotional video for a proof of concept research project called 'IllumiRoom'. The main game shown is Red Eclipse, but SuperTuxKart also briefly appears (implicitly as the game played by a girl!) around the 0:48-50 mark.
I doubt they were actually showing an Xbox as I'm unaware of either Red Eclipse or SuperTuxKart being able to run on one.
I find it fascinating that 2 FOSS games would appear this way. Either this is an indication of red tape avoidance (no permission required for GPL games) or a cultural shift within Microsoft - or perhaps I'm just reading too much into it.
It certainly adds some validation to the games themselves, indicating they are impressive enough to feature as part of a video by one of the world's foremost technology companies. So hats off to the developers of both projects and also the projects that enabled them (CubeSauerbraten, TuxKart) - I like it that both games are good examples of open source in action.