The first responsive creation I started on was the IR triggered blacklight. This has two basic parts: a gutted blacklight flashlight, and an arduino that triggers a relay when the correct IR signal is detected. 

The arduino uses a 3 pin IR sensor which is easily read with the arduino IRRemote library. I used the simplereceiver sample sketch as a starting point, changed the received command to match my Blaster, and write pin 11 low for a few seconds when the command is received. My relay can trigger on either high or low. I found that I couldn't pull enough current to trigger it high, so I use a low trigger. 

The IR receiving is working flawlessly and triggering the relay as expected. The flashlight is wired to trigger from the relay. The flashlight runs on 3 AAA batteries, so I'm running it off the 5V output from my arduino. It pulls about 120mA max, which is too much to power it off an io pin. However, with the relay and 5V line it should be no problem. Yes, I could have used a transistor instead. Relays are more fun though. I'm a mechanical engineer, not electrical. The flashlight is lighting from the relay as planned. There's no more work on this part until I get to the creation of the decorations.