The people over at the Bike Union host these picnics four times a year.
Focused on promoting bicycles as a viable means of transportation, the crowd varies with as many types of people, as there are types of bicycles. All ages are not only welcome, but in attendance. They'll have hot dogs and veggies to grill, but folks should bring whatever else they want to grill/eat/drink. There are grills on site, and it's an alcohol container free zone. At last fall's picnic I learned everything from composting, to solar electricity, to new bike routes, to adjusting shifters, and to how to play bike polo.
More details as they become available, just wanted to give a heads-up! Definitely a casual way to meet more bike peeps.