How long will you be there/will you have a car? When you say Traverse City do you mean near Traverse City?
If you have a car available:
Short's brewery is a short and beautiful drive from Traverse City and I will be so mad at you if you dont go.(http://www.shortsbrewing.com/
) The drive takes you around Torch Lake, one of National Geographic's top five lakes in the world, and of course to the west side is the beautiful Lake Michigan. Stop at one of the beaches at Torch Lake on your way back and take a dip. Or, drive back the other way and go to Pearl's (http://www.magnumhospitality.com/pearls/
A little bit shorter drive west is Sleeping Bear National Forest (Today show named Sleeping Bear the most beautiful place in the US last year or something equally as silly) The big dune is like a 50's tourist trap kind of thing, but there is a cool view from the top. I'd recommend skipping it and going further south to go tubing down the platte river with some brews. There is a lot of hiking here as well, mostly moderate to easy in terms of difficulty, but all beautiful.There is also a surprisingly nice scenic drive (Pierce Stocking) that is a nice place to stop and have a picnic. There is a drive in movie theater near the platte campground in Honor called The Cherry Bowl that is pretty fun if you've never been to one.
To the Northwest and up the Old Mission Peninsula, you can do wine tastings. Old Mission you have to pay for most of them, but in the Leelanau Peninsula I recommend going to L. Mawby (sparkling wines) and Boskydel Vineyard. Boskydel is owned by a very old grumpy man named Bernie (http://www.boskydel.com/winenazi.htm
). He was the first person to grow wine grapes in the area after reading about the similarities in micro climates between Northern Michigan and wine regions of France, while he was a Librarian at Northwestern Michigan College. He is a funny guy but very particular about his tasting room rules and hates big groups of people. So if you go there be chill. He banned a friend of mine for bringing too many people in at the same time. Mario Batali has a house on this side of TC as well as Jeff Daniels and Tim Allen. Watch out for Tim Allen because I hear he is a huge asshole. I dont know what Apples are picked in August, but this place (http://www.christmascovefarm.com/
) has some really crazy and interesting varieties.
In downtown TC, go to North Peak for casual dinner/drinks, and then walk along the boardwalk, down the river to the grand traverse bay and the beach.
For a fancy dinner, go to Stella. (www.stellatc.com
) I can not recommend them enough. It can get really pricy but it is possible to get out at like 20-25 a head for dinner and drinks.
Basically you can just hang out on the beach in TC and have a pretty good time. Depending on when you are there, the Film Festival that Michael Moore puts together might be happening (July 31-August 5)
I'll give you more recommendations as I think of them