Since I became an uncle last year, I thought about building something with electronics for my niece. I already setup a circuit a while ago for pulsating LEDs. I used this circuit for one pulsating blue LED and added another blue LED and a Yellow LED. What I wanted to achieve is that the LEDs illuminate certain parts of an image which is put in front of them. I used a food container where I could put in a mini breadboard and a 9V battery. I searched the web for free images to use and found a clipart page which had just the image I needed.
For the circuit setup please have a look into my old post.
Here is a demo of the nightlight: