Bert And Ernie Puns

What was Ernie's response to Bert when asked if he would like some ice cream?

Sher-bert! has to be said with ernie voice for full effect

I've had grown men steal this joke from me and claim it as their own..

We were visiting relatives in Canada last summer, including my Dad's brother (so, my Uncle) and his son Brandon. We were around the bonfire one night and Brandon was carving something for his girlfriend Emerald out of spare wood (it actually looked pretty cool). My Dad and Uncle saw the thing, it had a heart that said "B+E" in the middle. Uncle: "What's that supposed to mean, 'break and enter?'" Dad: "Probably 'Bert and Ernie'." Then they laughed like crazy. They joke around like that all the time when they get together, it's pretty hilarious.