I don't know another show where a main character suggests she's bipolar (Princess Fiona) nor one with a song rhyming classy and gassy. And I wasn't expecting to hear the line "Pull my finger!" used in a West End show!
I laughed and sang the songs all week. And I can confirm the show is participating in the Get Into London Theatre Deals starting in December. For now, enjoy these Photos from Shrek The Musical.