I often wake up in the morning with a song already in my head. Which song it is bares little resemblance to what I've been listening to or even like! I wrote about a whole series of them in my blog some time ago.
Shriekback- "Beyond Metropolis". It's the futuristic city names they made up, and the way they somehow fit them to the beat. Names like "Panchromosoniradiopolis" and "Metamorphopolyquantumopolis" and "Cerebrasophocognimelantragiopia". Wow.