JANESVILLE Years ago, on one of Bob Hillerâs days off, a friend pulled a prank using Hillerâs well-known Rollin Pin Bakery mobile food truck. In a good-natured ruse, the friend stuck a âNow Openâ sign on the street corner next to the food truck, which was parked outside Hillerâs home on Janesvilleâs east side. Hiller hadnât made any baked goods, and Rollin Pin was not open for business that day. But the joke fooled so many of Rollin Pinâs fans that within minutes, a queue of about 50 cars had lined up along the street.