What are your favorite casual games?

[bluesinG]

I'm interpreting "casual" to mean "easy to learn how to play." By this definition, my favorites are...

Wii Sports (Wii)
Rayman Raving Rabbids (Wii)
Guitar Hero (Multi)
Crazy Machines (PC)

Also, I loved Zack and Wiki, but I definitely would not classify it as casual.