My favorite is the Chintendo Vii.
Also, after I picked up the Chintendo Vii, I can NOT tell which one is my Wii and which one is the Vii. Seriously.
(sarcasm) 
I actually own a Wii knockoff called SwingZone Sports that I got when I was about 5 years old.

I actually couldn't tell the difference between that and a Wii.
Because I was a dumb kid.

(If I can ever get some gameplay footage or screenshots from it, I might upload it.)