You should try out the  Alpine Coaster, it is a toboggan-style car that slides down the mountain and is super fun. 

"You'll enjoy the beautiful Wasatch mountain scenery as the automated lift system whisks you to the top of the track. Then, hold on tight as you go whizzing down the mountain on nearly 4,000 feet of curves, bends and loops. It's a ride you won't soon forget." -from the website

I would highly recommend it!

Hey Ryan!

Lots of great breweries and bars up and down  Park City Main Street but we make sure to go to the Riverhorse at least one of the nights. It's upscale/casual, and fun to have a nice dinner with great atmosphere. It's been there for several years. 

In the summer there are really good deals since its not tourist season (winter).  Food options:

Windy Ridge Cafe near Bonzana Drive. (Taco Tuesdays during the summer.  Or any night their Southwestern Corn Chowder is delicious!)

Billy Blanco's in Kimball Junction.  They just opened summer 2013.  Mexican inspired biker bar, their Mango and Avocado salad plus the Chicken Lime Soup is great. (or the nachos!)

They are a number of resturants on Main Street, but I haven't yet eaten at one that I would recommend other than sushi.   Oishi Sushi Bar & Grill off main is the best in town in my opinion.

The best summer time activities are mountain biking and hiking.  They are a plethra of trails in different lengths and difficulty to pick from.  

Homestead Crater in nearby Midway is a natural hot springs surrounded by a rock dome.

Walking down Main street is usually entertaining as well, there are shops and people to watch.

Park City Mountain Resort has a ton of summer activities. From the alpine slide and mountain coaster to zip lines and miniature golf, there is something for every age. Deer Valley Resort has mountain biking (load your bike on a chairlift and worry only about the downhill) as well as an amazing amphitheater with summer concerts. Just outside of Park City in Kimball Junction, the Utah Olympic Park also features zip lines (more than PCMR) and an alpine slide (faster than PCMR)  as well as a run on the 2002 Olympic Bobsled track (A must-do for any thrill-seeker and well worth the $75). You can also check out the freestyle skiing aerialists practicing their jumps into a pool.