As Botanic Gardens goes -- or should I say, as Botanic Gardens grow -- Denver's is at a disadvantage. After all, Denver's climate is semi-arid, and Colorado is not known for riotously colored flowers. Still, the Denver Botanic Gardens is a pleasant place to spend an afternoon, especially when the tulips are in bloom. Their "kitchen garden" boasts a huge variety of herbs and edible flowers, and they have an interesting indoor conservatory. Their best event is the Mother's Day plant sale, where you can buy every imaginable house plant.