This isn't funny any more. I'm brushing my teeth, I'm washing the dishes, minding my own business and without advance notice discover I am humming or singing either the words or bass line from the Yes song Roundabout.
It has now been months. Months, my friends. A weaker mind would have snapped. A stronger mind would have bucked this somehow.
I did just discover the source though, and it has not helped. I haven't heard Roundabout in years, and, I must say, never on purpose. But I've been playing this pinball game on the Wii and one of the games has music that ends with a similar riff - just one measure. That planted the evil seed. But I refuse to stop playing the game. And thus I suffer.