Where do you get your data from? I've found sports data (especially odds/lines) to be overly expensive when trying to build hobby apps.
It's a "private" API for their website, but like I said it's been around for a while and using it in a hobby app isn't going to be an issue. Using it commercially is just begging for trouble, though.
[0]: http://www.espn.com/apis/devcenter/blog/read/publicretiremen...