If you love music but also enjoy working with electronics, this could be the project for you! Instructables member helenbang has created her own musical stairs.
As you walk up and down the stairs different notes are sent to a synthesizer on your computer. Each stair contains a sensor module which includes an IR sensor which allows the Arduino Uno controlling the project to know which stairs are occupied and which notes to play! You can watch her attempt to play happy birthday on her musical stairs in the video below:
This is a really fun project! To get started building your own musical stairs check out the full instructions, including code samples, at the following link.