I love the way it's a compilation of layers and layers of culture--and not just recent culture, it samples the Stones, Cyndi Lauper, Nirvana, Madness, Simon & Garfunkel, and tons more. It melds mellow memories of listening to my parents music with the aversion I have to mindless modern pop into something entirely new. The hooks that pop up literally every few seconds trigger fireworks of neurons that don't normally fire up together.
Yes, Girl Talk didn't write any of this music. He just stuck all the songs on top of each other in an amazingly complex, 71-minute amalgamation, olio, mashup, whatever you want to call it. It's genius. It's a cultural fun-house mirror that bends the sounds we thought we knew into something that's alternately amusing, weird, catchy, funky, ridiculous, and grotesque.
Here's a sample:
Feel free to download the whole hour-plus-long album here (legally!), but be aware that it has cuss words strewn liberally throughout.