Best time to go is Saturday mornings to late afternoon. There are street vendors, food trucks, and various local shops ranging from a coffee store, asian supermarket (a chinese and korean based one), chocolate store, etc.
You'll find Pamela's Diner here, Roland's - good place to get a drink, and if you want to pick up some Steeler t-shirts almost every vendor sells them!
This kept me occupied for a good hour to hour and a half. It felt a little sketchy around 4-5pm when the sun started to disappear and the streets a little emptier with the vendors packing up.