For 2014, Shell gas stations are offering 2 for 1 vouchers at several ski areas with a 10 gallon gas fill up. This means that if you buy at least 10 gallons of gas, you get a coupon good for a free lift ticket if you purchase one full price adult lift ticket. The deal is good at several ski areas.
Unfortunately, full price adult lift tickets have become so expensive that this isn't much of a "deal". But if you just want to ski one day at a participating resort this year, this will get you on the slopes for less than full price.
In Colorado, 2014's participating resorts are:
The SkiFreeDeals.com web site has a full list of participating Shell stations and ski resorts.