I knew about this, but never had the date/time info until yesterday:

http://ehilbert.wso.net/OSC/

OSC Fall GUN SHOW
Grange Fair Grounds
Centre Hall, PA
Saturday, Sept 15
Sunday, Sept 16
9 AM - 4 PM
130 Vendor Tables
Buy - Sell - Trade
Door Prizes - Gun Raffle - Food
Admission: $3