Gerard 't Hooft ended his Nobel Lecture by expressing his reservations about string theory.
There is still room for surprises, he said, as an image of magnifying glasses popped up on the screen behind him. If, ’t Hooft continued, we could actually see a string, there’s no telling what we would find. All of a sudden, music started playing, and the entire hall burst into laughter. As the magnifying glasses zoomed in, they revealed Taz—the Tasmanian devil from the Looney Tunes cartoons—jumping up and down on the string, using it as a tightrope, and pulling faces the entire time.
Having read so much about this talk in Only The Longest Threads, it's only fair that you should get to watch it for yourself.