To experience something of the American aristocracy's approach to 19th-century leisure, visit this museum. It lies inside the historic Newport Casino building (1880), which served as a summer club for Newport's wealthiest residents. The US National Lawn Tennis Championships (forerunner of today's US Open tennis tournament) were held here in 1881. A scavenger hunt, available at reception, gets kids engaged with eight centuries of tennis.
If you brought your whites, playing on one of its 13 grass courts (closed in winter) remains a delightful throwback to earlier times ($160 for one or two people per 90 minutes). Otherwise have a drink lawnside at the La Forge Casino Restaurant (lunch menu $30 to $35).