There are lots of fun things to do in the winter.
The weather is great for most any outdoor activity hiking, biking, golf, swimming, etc. The Indian Canyons are always fun great views and just fun to visit.
Shopping is always fun as are the casinos, there is usually someone interesting playing. Some may be oldies but they are fun to watch.
If you take the tramway up San Jacinto you can play in the snow.