ESPPony, who's a member of the Everypony Sings team and a truly talented instrumentalist, does these great videos where he records himself playing pony songs (with several instruments!). You can find them on his Youtube channel.
His latest cover is for B.B.B.F.F., and it is excellent. Watch it—you'll be glad you did! In it, you can catch him playing bass, electric guitar, acoustic guitar, and keyboard while Twilight takes the vocals. Why aren't you watching it yet?
ESPPony also wrote some excellent music resources so that you can play it yourself: a bass tab, an electric guitar tab, and an acoustic guitar tab.