The first Thursday of every month (I've even seen them in the winter) there is a Motorcycle riders meet up/gathering whatever you want to call it. Bikes line the streets, fill the parking lots. The meet up starts up at Duluno's Pizza which is on the corner of Lake Street and Garfield Avenue in South Minneapolis. On a nice summer day it's easy to see at least 1000+ different bikes of all makes/models/years.
If your on Facebook check out First Thursday Motorcycle Meet Minneapolis.