The most important is Palm Canyon, which is a very nice oasis in the middle of the rocky desert. Another one which is equally beautiful is Andreas Canyon, only a 10 minute drive from Palm Canyon.
Filled with palm trees, both places are a great opportunity to hike a bit along streams and in the shadow of the trees. It really is a strange experience to find water and groups of palm trees in the dead surrounding landscape.
Definitely worth a visit, when in the neighbourhood. Take 2-3 hours to visit them both. And again, bring lots of water.

