Also see Game Helpin' Squad's "A Pissed Off Tutorial For Google Wave":

https://www.youtube.com/watch?v=4Z4RKRLaSug

Their "World Quester 2" tutorial shines as the holy grail of consistent and ergonomic user interface and game design. The menuing system is so magnificently structured and well organized, it bring tears to my eyes. Google Wave pales in comparison.

https://www.youtube.com/watch?v=0Gy9hJauXns