A little bit farer away than the old Ouarzazate, but still easy to achieve in a day or a half day, here are a few proposals :
Ait Ben Haddou
This impressive fortress was built on top of a hill that oversees the plain around. It is listed as World Heritage by UNESCO. You need around 40 minutes by car from Ouarzazate, and you can visit it any time during the day (no light at night). You will need a little hour to reach the summit, where you can enjoy a wonderful sight. If you go there in the afternoon, you can enjoy the sunset over the hills before departing back to Ouarzazate.
Fint oasis
You need a 4 wheel to visit Fint oasis, south of Ouarzazate. It is one of the most beautiful places around, and even more during springtime, when the contrast between the fiels and laurels, and the desertic landscape around, with its abrupt and mineral cliffs near the river, is the strongest. In Fint, you can have a tea in a local house.
Skoura palm grove
One hour and a half away from Ouarzazate, eastwards, on the road to the roses valley, Skoura is a great oasis, where you can stay a full day, wandering in the shadows of the palm trees. Thanks to the wealth provided by the palms and the dates, the inhabitants of Skoura erected beautiful casbahs ; some of these casbahs can be visited.
Farer away from Ouarzazate
You can drive to the Dades valley, Merzouga or Zagora. But, except for Zagora, you have to stay a night there.