We usually buy the activity cards - check out the resort website and you can see what discounts/activities are there. massresort.com
We have taken the grandkids to Shenandoah Caverns, Frontier Culture Museum, Hall of Valor/New Market Battlefield - all free with the card. Magic show and comedy show are usually half off. My husband does golf and ski, and the waterpark we always enjoy. ALso a discount on horseback riding, sometimes on mini-golf. And one of my favorites - the discount on the wine tours
For kids (nothing to do with the activity card) they have kickball and other sports in the field near the playground that are led by the activity staff that my grandkids REALLY enjoyed. This was just friendly "neighborhood" type of playing with close supervision - great for all the younger kids who really did not know what they were doing!!