Aside from the beautiful singing, this also shows wonderful communication among the players in the orchestra. Watch for the ways they use eye contact, to be able to play so well as an ensemble without a conductor.
Saw a boy a little rose, little red rose on the heath, young and lovely like the morning. So he ran to have a close look at it, and gladly did. Little rose, little rose, little red rose on the heath.http://en.wikipedia.org/wiki/Heidenröslein
Purcell's theme, which appears on the Grade 1 syllabus in the book below, was used by Benjamin Britten in his terrific piece Young Person's Guide to the Orchestra. The first video is Purcell's original arrangement, the second is Simon Rattle conducting the finale of Britten's piece.