I honestly think Project Gotham Racing, the original Xbox launch title, would make for a good Game Dungeon episode. It's not as widely known as its sequel, the series it's in isn't as widely known since there hasn't been a new entry in a decade, and not only is it an eclectic racing game, it has an eclectic soundtrack with a lot of really obscure stuff, like this:
The only potential hurdle is that it's only on the original Xbox, but that's nothing some good capture equipment can't deal with.
Fun fact: it was the second best selling Xbox title after the first Halo, and Halo was the game that MADE the Xbox. If Halo somehow didn't exist, PGR would have had to try and make up for it, and as good as the game is, it wasn't quite the force Halo was. Sometimes I like to think what the console scene would look like if that had been the case.