No matter where you go, there's always plenty of things to do. It just depends on what your idea of fun activities might be.
As mentioned, winter sports does NOT come to mind when staying in Palm Springs. This is low desert and it's going to be warm. The Tramway is nice but I'm thinking it's not as you imagine. It's more a tourist ride to the top of a mountain with a restaurant and some hills for tubing. There was still snow up there when we visited last March but not enough to be excited about.
We spent time in Joshua Tree National Park. There is rock climbing and hiking available there. Probably some other activities but I didn't really check it out that closely.
The museums have been mentioned.
There are several nature tours that can be taken. We took a half day tour of the desert and San Andreas fault that we both found interesting.
There are shows, golf, casino's and shopping.
You can take a day trip down to the Salten Sea (sp?)
I have a photo album from the Palm Springs/Palm Desert vacation which includes pics from Joshua Tree National Park, The Palm Springs Aerial Tramway, Downtown Palm Desert and the Desert Advantures Tour. I can't speak for other timeshares but Marriott had a very nice informational session for guests where vendors came out to explain what they had to offer. It was time well spent for us.
This is the link to our photo album if you're interested.
http://dougp26364.smugmug.com/Trave...s-and/22163216_pqkTDN#!i=1769765320&k=5NMGpGg