A long time back, I had gotten these from Lego Racers. Extension to them are .Tun.
I believe they are the music/audio files to the game, but I have never been able to find a way to play this format.
Part of me wonders if these are a type of archive, or some sort of encrypted audio format.
http://www.jeffmakesgames.com/misc/LegoRacers.zip