Before Ron Howard was the great director, even before he was Richie Cunningham on Happy Days, he was little Ronny Howard playing Opie on The Andy Griffith Show. Opie was a ridiculously adorable child who loved him some ice cream. But there was just one problem with filming an ice cream scene. In the early days of TV, the lights were so hot it could make your make-up melt. It could certainly make ice cream melt.
In an interview with the Television Academy (think: Emmys), Ron Howard explained the first time he got ice cream on the set. He said his eyes jumped and he thought: 'This is gonna be great.' But it wasn't ice cream at all. It was actually "...cold, colored mashed potatoes/ You know, licking that, that takes acting: Licking mashed potatoes to make anybody believe it's ice cream." Check the video starting right around the 24:45 mark.
So yeah, not real tasty -- especially when you really wanted ice cream.