Fodor's Expert Review Sabino Canyon
Year-round, but especially in summer, locals flock to Coronado National Forest to hike, picnic, and enjoy the waterfalls, streams, swimming holes, saguaros, and shade trees. No cars are allowed, but a narrated tram ride (about 45 minutes round-trip) takes you up a WPA-built road to the top of the canyon; you can hop off and on at any of the nine stops or hike any of the numerous trails.
There's also a shorter tram ride (or you can walk) to adjacent Bear Canyon, where a rigorous but rewarding hike leads to the popular Seven Falls (it'll take about 1½ to 2 hours each way from the drop-off point, so carry plenty of water).
If you're in Tucson near a full moon between April and November, take the special night tram and watch the desert come alive with nocturnal critters.