The "Henry" to whom Ruff often speaks with on the phone is a reference to former WGBH president Henry Becton, Jr.
During filming of the series, Ruff's voice actor Jim Conroy would record his lines in an audio booth while ad-libbing to the contestants' reactions. After each shooting, he would then travel to New York City to record further lines for the animation.
The series has had crossovers with other WGBH programs and their personalities, including Norm Abram from The New Yankee Workshop (1989) and This Old House (1979), Nathan Ball from Design Squad (2007), and Gary Sohmers from Antiques Roadshow (1997).
First season contestant Taylor Garron was previously a cast member for the last season of the WGBH program Zoom (1997).
Seasons 1-3 featured a real-life basset hound named Murray working as an assistant for Ruff on the show. After the dog playing Murray passed away, though, the character was retired from the show and replaced by a bulldog named Tank.