Alongside Highway 97 south of Bend is a dormant cinder cone volcano, Lava Butte, and you can drive, bike or hike up the circular road to the rim. Then you can hike around the rim trail for magnificent views of the surrounding lava beds and mountains, some snow-capped. There is an enclosed tower, too, for those not inclined to hike the rim trail. An interpretive visitor center is located at the base of the crater with paths through the lava beds.
If you go:
Lava Butte road is seasonal May through Mid October. You must obtain a 30 minute time pass at the visitor center before ascending by car, as parking at the summit is limited to 10 vehicles. Fee area.
Links:

Lava Lands Visitor Center
58201 U.S. 97
Bend, Oregon 97707 USA
Mailing address:
Deschutes National Forest
63095 Deschutes Market Road
Bend, OR 97701 USA
Phone Numbers:
Lava Lands Visitor Center
+1 (541) 593-2421
+1 (541) 593-2421
Deschutes National Forest
+1 (541) 383-5300
+1 (541) 383-5300