Fair-trade Chicago fashion label Mata Traders is hosting a two-day Sample Sale and Focus Group Party at the label's studio/warehouse, 5215 N. Ravenswood Ave., from 4-8 p.m. Tuesday and Wednesday. The open house-style event gives participants a chance at deals on fall merchandise, samples and marked-down clearance items, plus a preview of Mata's spring collection. Participants will also be asked for their opinions about the spring collection for a focus-group survey. Refreshments will be served.