Its been a while since I have posted any good physics games.
World of Goo is probably my favorite. It is available as wiiware, and is simple and intuitive to operate, but has a pleasing complexity. Generally you move around bits of goo that build towers, cantilevers, bridges, and so forth. Some goo can be reused, other types can catch on fire or be used as fuses.
Tiki Towers is also available on wiiware. The idea is similar to World of Goo - building structures to get to point a to b. Here you are saving the monkeys, and possibly rescuing a few as well. In this game you are using bamboo to build with, and you have a few additional capabilities (reinforcing joints for instance) However, you got a baddie that can catch a segment on fire or turn it into rubber. The game is a little more difficult to control, and a little more challenging than Goo.
If you have a few minutes to burn while you are sitting at the computer check out this site. There are many games to play, straight from your browser.