A great place to get out and walk or bike is summertime Kirkwood  (1501 Kirkwood Meadows Dr. off Hwy. 88, Kirkwood, www.kirkwood.com , 209/258-7360). Without snow covering them, the slopes of the ski resort become great mountain biking tracks. For $30 (adult) or $15 (youth) per full day, you can take two different lifts up the mountain with your bike, then ride your way down.
You can rent bikes from Kirkwood on the weekends, and hone your skills at the clinics held several times each season. The bike terrain opens for business in late June every year, and closes after Labor Day.
If you prefer your own two feet, take the lifts up (or don’t, if you’re strong and energetic), and hike down the multi-use trails to the lodge any day of the week during the summertime. Check the Kirkwood website for scheduled guided hikes and wildflower walks throughout the season.