Ride the Carousel of Happiness in Nederland, Colorado
This is a cinch to recommend. Nederland is a fun little mountain town about 20 miles up Boulder Canyon from Boulder, and on the way to Eldora Mountain Ski Resort. It's an easy half-day trip from Boulder and well worth it.
For $1 a ride, your kids can go up and down and round and round to the sound of old-timey music played on a 1913 Wurlitzer band organ, on a restored 1910 Looff carousel. The 36 hand-carved animals are the work of Scott Harrison, a local veteran who has spent the last several decades creating them.
The Carousel of Happiness opened on Memorial Day 2010. It is a nonprofit venture; hours vary; tel. 303/258-3457.