Without a doubt, Wii gyud if your thinking about getting your parents involved in gaming bro, and I'm basing this on personal experience. Pagpalit gyud nakog Wii ug pag-abot sa balay nya ang gi-play lang nako kay Wii Sports Resort NAH! NANGDULA GYUD NOT ONLY MY MOM BUT MY DAD AS WELL.

And from what I reckon when I was younger, BOTH my Mom and Dad HATED the idea of me playing videogames (true story) NOW, THEY'RE ENJOYING THE THING THEY HATED IN THE FIRST PLACE. DALI RA GANI SILA NAKASABOT UG DULAG MARIO PARTY 9 SAD SILA Hahahahaah!!
I dunno if it'll work if I get a 360 with Kinect tho, kay gatigum pa ko ana (and probably a PS3. . .probably) Wii U sad pwede kau (but I haven't seen one yet here)
But I think when it comes to motion games, I guess there is NO AGE LIMIT. I have to agree that they are FUN and they're everyone. There is truly a bright future for motion games.