Brass Ensemble - Level 3 - Digital Download SKU: A0.982221 Composed by Jaret Reddick. Arranged by Shawn Postell. Contemporary. Score and parts. 54 pages. Encore Music LLC #6267095. Published by Encore Music LLC (A0.982221). The Theme from Phineas and Ferb Today Is Gonna Be A Great Day is written for a flex-ensemble; whether a traditional woodwind quintet, brass quintet or any other combination of five instruments with percussion (or without), here's a grade 2.5 version perfect for your ensemble looking for something fun and familiar.