I notice it every time. I go to wrap a gift, and it seems like all the gift-wrap just doesn't add enough expense to the project. How to make it more expensive? What about adding a microcontroller to the wrapping?
Step one is to dig through your boxes of hardware until you find that little tube of attiny13s that you ordered a long time ago. Next up, you need to write a little code that will blink LEDs on PB1-4. Using those four pins makes it pretty easy to do a nice 4-way symmetrical arrangement of LEDs.
Program it and make sure it works on a breadboard.
Next up, solder the cathodes of all the LEDs together along with a little piece of wire that will connect to the ground pin on the microcontroller. Trim the anode wires to make space for the attiny13.
Finally, flatten the chip out, bend the VCC pin around the top (it will make contact with the battery) and solder the LEDs to it. A little piece of wire-wrap wire can wrap around to the negative side of the battery where it is held in place by some tape.
When doing things dead bug style, it's more traditional to have the device sit on the ground plain, with VCC coming in on a wire. I opted to switch things around because I wanted to make sure that if the chip got tilted so that one of the LED pins touched the battery it wouldn't create a dead short that might toast the chip.