From LazyTown Wiki

Upphaf is a song in Glanni Glæpur í Latabæ. The word 'Upphaf' means 'beginning' in Icelandic, as it was the first song used in the play.

Though made primarily for Glanni Glæpur í Latabæ, the song was found to be very versatile, eventually being used in most LazyTown television episodes, DVD menus, and the like.