Interesting topics today include Defend Your Castle (pictured), a riotous romp of quick gameplay and hilarious art, and Strong Bad's Cool Game for Attractive People (and you can play too!) which is essentially exactly as you expect.
Both of these are available for the Wii, and are loads of fun. Props to everyone who tipped me on to these (Aaron, Tiff, and .. Kyle for SBCGfAP?)
If you want to test your physics skillz, I would recommend fantasticcontraption.com. Its an extremely addictive game that has recently been blocked at work. Once you beat a level, you can take a look at what other people have used to beat it. Some people go to great lengths to make a complex contraption to do a simple task.
There's only room for one fantastic contraption in my house.
Seriously though... fantasiccontraption is the shit.
so have you tried http://fantasticcontraption.com/ yet? as soon as you do i'll send you some of the crazy ones I came up with.
I gave it a shot but didn't get very far. The notion of wood and water rods was a little goofy (although admittedly not as goofy as Defend Your Castle).