Now that computers have knocked off the best human games, how about some more realistic type problems. My suggestions:
(1)Writing a top ten Country or Pop single (words, music, and production).
(2)Given an appropriate budget and the necessary geological and terrain data, design a gorge spanning bridge that passes muster with top civil engineers.
(3)Given an elementary or intermediate physics textbook, use natural language understanding to read it and solve the problems. It's program can include all appropriate background, but not the specific content of the text.
(4)Write a Tony Award winning Broadway Musical.
(5)Devise and implement a program to control and mitigate the adverse effects of humans on the global environment;-)