Hans was generous enough to help out with judging the 555contest 2 years ago. It was really great getting to correspond with him and even better getting to see all the fun things people did with the 555 chip.
Sergio was my professor at SFSU in the 80's. I have fond memories of getting photo copies of a new chapter each week of his Op Amp book that he was writing at the time. I have recently read (but cannot remember exactly where) that you can make almost anything using 555s. We are getting to the days when many of the innovators are gone. Williams, Pease, Jobs and now Camenzind. The real question is where is the next wave of innovators going to come from?