"C Eb F G Bb C". As these are the notes of the C minor pentatonic scale, I thought that scale wouldn't sound any good over any C major chord progression, as the Eb and Bb aren't present in the C major scale.
You know, I've had a plan for quite a while now. Just try to create a little song, which starts very dark and minor sounding. Then half way through, change the mood completely, and make it as major as possible - well, more or less. Just to explore how things get to sound minor and major, and to hear the constrasts.
Imagine a very heavy death metal song, and when it comes to the guitar solo, it appears to be an extremely happy solo, then as the solo is finished, the songs continues in its dark and gloomy direction again.
Not a revolutionary idea, I know, but I haven't tried it before myself. I think it sounds interesting, maybe I'll create something already tonight.