I love love love The Milkshake Factory!
After finishing the half marathon I desperately needed dessert. My visit was later in the afternoon so it wasn't crowded at all. The staff is super friendly and accommodating. I alerted them of my peanut allergy and they made my shake completely separate. I order the S'mores shake and was not disappointed.
They also have all kinds of chocolate covered items for sale. It's the perfect place for a small gift. They also have sundaes and other treats outside milkshakes.
Street parking is available. Garages in Market Square or PPG are usually the easiest.