The entire experience would be much more interesting for students if they could compete with friends (like with apps on facebook, for example), but I'm not sure making yet another FB app is a good idea here, plus you'd be stuck competing with other music theory students.
My half-baked idea is a central educational social networking site in which you could earn education points by achieving scores on lots of different member sites, not just mine... so a music theory whizkid might use their stats/achievements/reputation/karma/whatever to compete with their math nerd friend, even though they're focusing on entirely different specialties. There'd have to be rough equivalency in the effort involved to achieve points on different sites, but that's not a big hurdle (and weighting could be adjusted automatically based on students' relative speed of advancement.. if students tend to go tearing through achievements on a given site, the value of its points would be reduced in the global stats).
I'll dig through some of the sites linked above when I have time, but at the moment nothing seems to match up with this concept.
Is this a good idea? (Is there anything out there heading in this direction? I don't have the time to develop it myself currently, though I'd happily offer tons of advice).