Actually, 25 or 6 to 4 is about writing a song. At least, that's what Robert Lamm says. And since he wrote the song, it seems like he ought to know. Cite: http://www.straightdope.com/columns/...or-6-to-4-mean
I believe Clapton's Tears in Heaven is about the death of his 5-year-old son, who fell out the window of a 50 story building.
I like this game but I can't think of any more right now.