Just last night actually. I attended a sing-a-long Christmas party. There was a game where we picked pieces of paper out of a stocking, on the paper was a song, and something we had to do with the song.
I picked a piece of paper that had me organize everyone into different groups to sing the different parts of '12 Days of Christmas'. Turns out rather well.
This year on Halloween, we usually go caroling but didn't go this year. On Halloween our rather large group has a tradition of singing Christmas Carols when the kids ring doorbell at our friends houses.
All the time lately. My daughter plays the piano and her lessons revolve around Christmas music this time of year. She sings while she plays, and I tend to sing along while I bustle around getting things done.
Pretty much all year round actually...most recently would probably have to be about a week ago when I was baking a batch of cupcakes and mixing up some homemade chocolate frosting to go on top.
My favorite Christmas album is Tennessee Ernie Ford's "The Star Carol", he has an incredible voice that works perfectly for more traditional carols.