No matter what time of the year you're planning your holiday, Denver is always a good option. You'll love checking out the Red Rocks Amphitheatre, and your kids will have a blast at places like the Museum of Nature and Science, Water World, and the local zoo and aquarium. If you want a more relaxed day with your kiddos, hop on a Denver Trolley, and take in the city and mountain views from the open-air streetcar.