Small children, older children, grand parents - no problem. Odense has several attractions that can entertain your entire family. Go time travelling, visit the animals at Odense Zoo or something else entirely.
History can be a somewhat dusty subject, but in Odense you can take your kids into our near and a bit more distant past for a hands on experience. Try the Viking Age, the Iron Age, 18th century life in a country village, the Cold War and even a teenagers room in the 80's.