What are games that take place during Christmas time, or have prominent Snow levels? I'm looking to get into the Holiday mood. It can be for any major system, and any genre.
Surprised no one's mentioned this yet, but the Animal Crossing games fit the bill.
We Love Katamari has a snow level where you're rolling snowballs.
Also, what schuerm said, and I'd like to add that many JRPGs are the same way. Final Fantasies VII and X in particular have some memorable snowy sections (Icicle Inn/Great Glacier and Mt. Gagazet).