Each year the Ann Arbor Mainstreet Events organization blocks the streets of downtown Ann Arbor and some 250+ cars line the streets.   There is always a great turn out of some pretty special cars including a number of Porsches.   Stroll the streets and take in the cars and the wonderful places to eat and drink.    There is no cost to attend the event and to show your car there is a pre-registration required, typically it’s a $35 fee.   See the link below https://mainstreetannarbor.org/rolling-sculpture  .   Note if you plan on showing your car, you’ll want to arrive in the early afternoon as they stage the cars before the people show up.