Intro: DIY LM3914N VU Meter
Part of learning about electronics is just messing around with LED blinkies - lights make everything better! Well, the LM3914N is a led bar driver, that is, it can, with some power, light up a bunch of LEDs at once in response to a signal. In this case, VU meters respond to audio signals and essentially shows the volume as a function of voltage.
This video shows how to set one up, and some of the troubleshooting I had to use to get it working the way I wanted it to!