Sanoja: Sesame Street. Alphaquest.

A black girl runs up and down a hallway filled with doors.
The animated effect on the doors has letters floating behind them all.
On the last line, she finds a door with one letter on it, reads it and then opens it to begin her latest adventure.
Short and sweet but I've had a LOT of requests for it.)

Doorways up and down the hall
Wonder what's behind them all?
Doors that lead to anywhere
Got to A, B, C what's there

Got to A, B, C, Decide
Where's the door I haven't tried?
A, B, C, D, East and West
Going on an Alphaquest!