There are wallets on Iphones now and people have garage sales every day. All you have to do different is put up and pass out flyers like a week in advanced. Even if no one comes (people will come to a flea market, but maybe not a garage sale) you will raise Bitcoin awareness with the flyers.
I plan on doing this myself very soon
As well as making Facebook events so that we can meet in mass to trade Bitcoins, instead of one on one.