Address Santa Isabel 52, Madrid, Spain Map, Tel 914-675-062 Call, Hours Mon,Wed-Sat 10am-9pm; Sun 10am-2:30pm Website
Not only is the artwork (including Savador Dali, Miro, and other modern artists) kid friendly (though you might think twice about bringing small children in to look at Picasso's Guernica), but this building has big glass elevators on its exterior making it fun to visit. There are benches outside the galleries for kids to stop and have a snack.
Check the museum's website for a schedule of Children's Activities at the Reina Sofia