I start with a comprehensive list of all the recent songs that have been big hits - and then I go down that list and see if I can come up with funny ideas for them. I can always come up with ideas, but not necessarily good ones!
In a genre where most of the artists are one-hit wonders, I've been able to hang around longer than most "serious" acts. I pride myself in being a very talented leech.
I cut my teeth playing rock songs on the accordion when I was a teenager and my friends always thought that was extremely amusing. I think that was the genesis of my polka medleys, because every rock song I played on the accordion just sounded like a polka and my friends thought it was funny. So that was a joke that I continue up to this very day.
It fit pretty nicely into my schedule because we'd pretty much finished the bulk of promotion for Mandatory Fun and were just getting geared up for the World Tour so this was a nice time for me to be working on it.