DM's question in United States

Food / Nightlife

What should I do / where should I go on the down days of a ski trip at Mammoth?

You check out mono lake or go down to Bishop and check out the Volcanic tablelands' petroglyphs
There are some great Hotsprings in the area especially near mammoth if you ask around. If you don't want to hiking around looking for them then go the keough Hotsprings outside of bishop. If you don't want to pay than wait till they close around 7 and you can get in the Wild Hotsprings under the… 
Also some of the best bouldering in the country is in bishop at the buttermilks.
Depending on weather there's tons to explore on the valley floor. Hot springs, off reading on quad bikes etc. also don't miss the cheese steak at the mammoth brewery.
If you have time, head over to June Lake to go hike and stop by the June Lake Brewery. Thy will have a food cart across the parking lot that has tasty Hawaiian food