What Do American Pie's Lyrics Mean?

When the jester sang for the King and Queen, in a coat he borrowed from James Dean. Now the half-time air was sweet perfume. No angel born in hell could break that Satan's spell. Who broke the church bells? And what really was revealed 'the day the music died?'
As the original manuscript for Don McLean's 1971 classic 'American Pie' is sold at auction, fans may finally discover what his song is really about. So what are the popular theories?