I was just looking around the net today and came across this interesting link. I've signed up to the Webinar that's coming up on 10th May so will try to remember to post more after that. Having an undiagnosed son in his mid - 20's who spends all day every day sitting in his room all day playing games, I found this really interesting. It's not a quick fix but with a bit of work this might just work.
The commentator is a young man with a diagnosis of Aspergers and he is the Co-Founder of the group providing this information. It's called "How to Easily Motivate someone with Aspergers".