I had a Snowman Party last year for my son.  I find it harder to find unique ideas for winter babies. I had computer paper that had dancing snowmen down one side that I bought on clearance at a discount store about 2 years ago and it was my inspiration.   So I used it to make invitations. I ordered a snowman icecream cake, I made a large snowman out of poster board and made craft-foam carrots noses and we played Pin the Nose on the Snowman. We made a snowman craft using large and small marshmellows for the body and pretzels for the arms and to stack the marshmellows. (2 large marshmellows work better than 3) and different candies to decorate with,  glued on using icing. They took these home and are completely edible. I made paper snowflakes and strung them on fishing line and hung them from the ceiling for a winter wonderland astmosphere. I kept out all of my snowman, christmas ornaments to decorate with.  It was amazing. After cake and icecream the kids got dressed (invitation indicated that we would be going outside so please send appropriate clothing) and we went outside to build a snowman and decorated him with a homemade snowman building kit that I gave out as party favors.  While we waited for the parents to pick up their kids we served hot chocolate outside. The snowman kits consisted of a plastic container that I bought at the dollar store and affixed a label too.  Inside was a felt hat(bought at a dollar store), a carrot nose, buttons and eyes. The nose, and carrot nose were made of paper mache that I painted and then clear coated with spray shellac to protect them. The buttons were just large black buttons.