One thing i would LOVE to see is a person (account-based) calendar. Players can add events to days/times, set it up to give an email notification, and there can be pre-loaded sets (dropdown menu where you can just click it and it'll put them all in or take them all out) such as Normal Tournaments, Special Tournaments, etc.
Normal Tournaments could be 1 color
Special Tournaments another color
Custom Events a third color

The calendar would be accessible in the client itself and also on the website.