Have him hold the remote all day. Tell him he has to do up and downs for an hour if he doesn't produce the remote at the end of the day. Tell older brother he gets a new game if he can slap it out of the youngster's hands. Tell Mom she gets a night out if she can pry it from him. Tell the neighbors and cousins they get $5 if they bring you the remote. Do this every day until he produces the remote. That will teach him not to fumble. (This has the added benefit of fostering fond memories between your boys so there will be no resentment as they get older.)
Ask him what the capital of Thailand is. When he answers, whack him on the head with the Wii controller.
I think the fact the poor kid has to listen to hours upon hours of discussion about the Gizmondo (and what could have been) is punishment enough. Give him back his Wii already!
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ih=009&sspagename=STRK%3AMEWN%3AIT&viewitem=&item=190074152402&rd=1&rd=1 i just purchased zelda: twilight princess for only $30 o happy days! cant wait to play it!