Brilliant! Loved the minimal interface. Awaiting graphs.

Would it be possible to provide a search bar to search for leagues on the homepage ?

"Keeping URLs safe" seems to be too geeky. I personally don't mind but my friends who join my league won't be so tech oriented.

EDIT: Also, you ask for the league name while creating it. might as well make it convenient for users to use that name. Separately, the URLs for the leagues could be simplified to contain the name instead of numbers.