A white elephant gift exchange. Another great one we do at our church is to do The Left-Right Christmas Game: Pass It On!

I would include Black Mystique's suggestion. For me the fun is in the socialization. I'd let the seniors help decorate the tree and room if they are able and willing. It is a little late in the season for it not to already be done though. My Christmas decorating routine includes hot cocoa with a candy cane (sugar free for the diabetics) and Christmas music to sing along with. I know this is more of a grade school thing, but I've always liked the idea. Have everyone write something nice about each person then at the end consolidate all the nice things said about each person and give it to them. Maybe just slips of paper? You will probably know better than I how much excitement they can handle and their energy levels. If they are easily tired, you may want to do something like the 12 days of Christmas with an activity each day leading up to the gift exchange, but like I said its a little late in the season to be doing that now. Maybe next year? You could have them make a different decoration each day to put on the tree. Personally I like decorating my tree with edible ornaments so there is less to put away and store for next year. Have fun!