The most fascinating rock formations from ancient volcanic ash... "moonscape" or "smurf land" There is a $5 per car charge and well worth it. The road to the Tent Rocks in paved and has a bathroom facility and picnic areas with tables and some with shelter.
From Santa Fe, take the Cochiti Pueblo Exit 264 off I-25 onto NM 16. Turn right off NM 16 onto NM 22, and follow the signs to Cochiti Pueblo and the national monument.
http://www.tripleblaze.com/trail.php?c=3&i=8194