Volcano

 Mt. Mcloughlin is THE premier classic summit in Southern Oregon, and in the top 5 for the entire state. The USGS tags the volcano at 9, 495 feet, giving it about 5000 feet of Prominence.
The ascent is a nice day hike, gaining almost all of that 5k of prominence in about 5 miles. The last 800 feet makes for a fun scramble.

Just for fun: the Pacific Crest Trail connects to the Mt. Mcloughlin Summit trail. Tack on the return to journey via Four Mile Lake for a great overnight trip.

Bonus: Check out the vast fields of Andesite (volcanic rock - post eruption) just off the trail as you go through the lower forests.

Pics taken with my phone, so sorry for the low res.

Looking out over Four Mile Lake and Klamath Lake (as seen in the distance)

At Timberline

Aaron and me at the summit