How classy can one video game theme be? Just ask the Triforce Quartet, the dapper gentlemen captured performing the Super Smash Bros. Brawl theme here. It's sweet, sweet music to my ears, and I surmise it will be to you as well. String music renditions of tunes are some of my favorite tracks. I could listen to them forever, but I get bored and switch to Era Vulgaris instead.
The Triforce Quartet is quite profilic as it is, and they're only gaining steam, having performed music from Halo, Zelda, Mario, and other popular scores at events like MAGFest and more. They also seem like pretty cool dudes who doesn't afraid of anyone.
Check out their rendition of the Super Smash Bros. Brawl theme and then go listen to this awesome Mario medley.