I love clothing swap parties!
My first clothing swap was an event hosted by Yelp in my local area. It was great! Over 100 women showed up for an evening event poolside at a local hotel. There were cocktails and the pool cabanas had curtains on them and were used as dressing rooms. Women got a voucher for one free item for every item they brought, with a max of 8. I got some great finds! Also, such a large event was nice because there were clothes for every size and style. Not to mention some great accessory pieces.
Since then, I have been hosting a clothing swap party at my house about every 6 months or so with my girlfriends to clean out my closet and get some new clothes. I like to have cocktails or finger foods and some music. Then I make it a mixer by inviting friends from different groups (work, school, old friends, etc.). We always donate the unwanted items to a women's shelter.
Now that I am pregnant, I also have been loving getting used maternity clothes. I haven't had a maternity swap party, but some friends and family have given me old maternity clothes and I've been using the Yerdle app (iOS) to receive gently used maternity clothes. I plan to post them back up on Yerdle (or donate to a friend) when I'm done with them all.