Ski resorts are considerably more boring in the off-season, with your activities pretty much limited to hiking, mountain biking, and dying at Action Park. Thinking creatively for off-season fun is Camelback's Mountain Adventures
Because skiing on dirt can be fairly painful, Camelback set up Mountain Adventures to give you something to do before painfully skiing on "snow", including a smattering of activities that'll test your fear of heights, none of which, sadly, include a chicken fight on Shaq's shoulders. Ground-based activities includes a 9-hole frisbee golf course running in and out of ski routes and woods, a Euro-bungee (essentially a slingshot/trampoline allowing for 20' jumps/flips), a 24-foot rock climbing wall, and a two-hour excursion on a souped-up off-road Segway equipped with what everyone's always wanted from a Segway: beefier tires, to take you out of range of anyone who might see you on a Segway. Elevation's achieved via 1,000-foot ziplines that'll have you careening 85 feet in the air across ski slopes, as well as the mack-daddy attraction, the Tree Top Challenge: a three-hour endurance event set in a network of trees connected via suspension bridges, swinging logs, and scramble nets broken up into five courses, letting you conquer sites like the Pharaoh, Cliffhanger, and the Asp, though you'll always be tied to a safety cord to keep from busting same
If you want to shack up, there's a full gamut of lodging nearby, and though it's set up for weekends, wrangling a group of four can get you in on a weekday, also known at Action Park as "maybe no deaths-day".