My mom and I both have iPad 2's and we're using the same apple ID for the AppStore so we can share the apps we pay for. I use game center to play games against friends and there's a new game I downloaded that I'd like to play against my mom. When I tried go log her in under her own apple ID it kept asking for the password for my apple ID (since it's the one being used for the app store). Is it possible to use a different game center ID from the ID being used for the app store? Thanks.