(The scene opens in the backyard. Phineas is lying under the tree and Ferb is beside him, reading.) Phineas: You know, Ferb, one of the best times we ever had was when we built that rollercoaster. (pauses) We should do it again! But this time...as a musical! Whaddya say? We'll do all the same things, except we'll break into spontaneous singing and choreography with no discernible music source! Ferb: Hmm...what assurance would we have that everyone else will also break into song and do the same thing? Phineas: I don't know. I think they probably will. Ferb: Fair enough. I'm in.