We sail in two weeks so I can post more after that.
In 2001 I recall the pizza area being open 24 hours and it also offered some salads and calzones.
The casual dining area (buffet area near pool usually) is also open 11-1pm & 6-9:30, as an option for those not wanting to get dressed up for dinner. The deli hours (sandwiches) was 11am-11pm, grille (hot dog,hamburger,chicken) 12pm-6pm and Asian Cuisine area 11:30am-3:30pm only. That was in 2001, but I am sure same hours may apply. We did not use room service, but plan on it this time--I would call it a light menu of some sandwiches,salads, snacks etc.
Adventure of the Seas RC April 2008
Carnival Liberty April 2007
Carnival Miracle April 2005
Carnival Destiny June 2001, July 2005
NCL Southward June 1985 Honeymoon!