This is the riddle posed by Neelix to Tuvok in "Riddles":
Neelix's answer is that he ate the dates. (calendar days) Tuvok suggests the sundaes. (Sundays)
I thought about it for a while, and managed to come up with one more. Petit fours. (All the little number 4s)
A lone ensign finds himself stranded on a class L planetoid with no rations. His only possession, a calendar. When Starfleet finds him twelve months later, he's in perfect health. Why didn't he starve to death?
Neelix's answer is that he ate the dates. (calendar days) Tuvok suggests the sundaes. (Sundays)
I thought about it for a while, and managed to come up with one more. Petit fours. (All the little number 4s)