I live in San Francisco, but spend much of my time during the winter at our rental on Donner Lake in North Tahoe. Mostly I ski in the backcountry or at Squaw or Sugar Bowl. Sometimes, though, I'm with people who don't ski, or are not quite comfortable on the terrain I like to frequent.
I found the perfect spot for those days when you're with people that want to hang out outdoors, but aren't up to the steep and deep. Royal Gorge Cross Country Ski Resort is awesome. It's the biggest cross country ski resort in the country. It's located just off Interstate 80 in the Soda Springs area. You'll get views of area gems like Castle Peak and Donner Peak. A full day pass is around $30 and rentals are another $20 or so.
You get all types here from the beginner trudging along with rentals to the bad-ass skate ski racer whizzing by. The trails are groomed for skate or classic (if you're not sure of the difference, see here) and there is a ton of terrain from easy to expert. There's even a nice little bar at the lodge where you can warm up with a hot whiskey at the end of the day.