Well... the course is pretty wet and playing a round of DG may want to wait a few days but the proshop is open and has pretty much anything a disc golf addict could want. If new discs, bag, towels, shirts etc... aren't enough there's always the trusty gift certificate. Morley Field proshop is open 365 days a year! If that doesn't cover it here are a few other inexpensive ideas that a disc golf geek may be interested in.
iPhone Apps Disc Golf Caddy iDisc Golf Pro Disc Golf Score Sheet Disc Golf Tracker Pocket Putt
and of course if your disc golfer owns a PS3 then this is a must have... Sports Champions - PS3
(bold = highly recommended)