Push button LED puck lights are pretty boring on their own. Take it apart and solder in a UV bulb for a DIY blacklight.
Replace the standard white LED bulbs in puck lights by prying the light apart, and heating up the solder holding the bulbs in to release the LEDs. Then solder in some 5mm UV LED bulbs and reassemble the LED lamp. Alternatively, you can use coloured holiday LED bulbs for a bit of fun.
Polarity matters, so remember the longer length pole on the LED bulb is the positive and solder it to the corresponding marked position on the light board. Once you're finished, you'll have a cheap light you can push to turn on and off, and will last forever on a single battery. Check out the video above (and linked below) to see how it's done.
Quick and Easy Dollar Store Electronics Hack [Via YouTube]