HELP,11 year old won't do anything but play video games!!?

my stepdaughter is 11, and my husband got her interested in videogames very early on in her life. now she is very overweight (170 lbs) and i can't get her to do anything else. when i talk to her father about it he says he will limit her time, but never sticks with it. i've been her stepmother for 8 years so i can't blame it all on her parents though. does anyone have any serious ideas for expanding her interests or getting my husband to understand the situation better?