Best rainy-day activity with the kids

A giant aquarium, a pretend shooting range, boats to climb on, tents to test, giant stuffed catfish pillows, hot dogs, fishing equipment no one even knew existed, a driving and putting range--what more do you need to keep the kids intrigued for a few hours, short of a Pokémon? Hell, if you're really lucky you might just catch an elk-calling contest or a seminar on muzzle-loading techniques, and there are always those fly-tying demos.