Programmable birthday card (I got it from Walgreens)
3.3V arduino (like the arduino pro mini
or arduino FIO
Wii Nunchuck arduino adapter
(or make your own like I did)
3.5mm female jack
I used an arduino FIO for one and an arduino pro mini 3.3V for the other because that was what I had on hand. This instructable shows the FIO because it was a bit easier than using the pro mini.