Hey, I have to make up words all the time; usually for songs which we have been performing onstage for years. I become so familiar with them that I tend to let my mind wander while I'm performing--thinking about the next song, thinking about the audience, thinking about the next set, and suddenly the instrumental break ends and I have to sing something. The family has become accustomed to hearing totally new verses to songs which we have performed for years. Sometimes I concentrate so hard on not letting my mind wander that I forget the words!