I thought the segment with Penn's offspring, Moxie, was fantastic. At first I thought it was all a setup, but after watching a second time, I'm convinced he was really surprised to see them there.
And Moxie did a great job! Not surprising, since they've grown up with magic, and assisted the old man on stage many times, as well as performing on their own.
I think Moxie really did fool the guys, too.