Arisia will have a 24 hour Con Suite with beverages, munchies, and the occasionally treat.
In addition to food at the Hyatt's restaurant and bar, the hotel will provide 24 hour quick meals in the lobby and buffets for breakfast, lunch and dinner. You can see the (the buffet menus will change from day-to-day).
For other food options near the hotel, you can see last year's Area and Dining Guides [1] information.
Links:
[1] http://2008.arisia.org/area_dining_guides