I was searching for a cheat sheet of commands that Apple's iPhone recognizes. (I can't afford the 4s with Siri). I found my answers on ATMac, a site for disabled Mac Users. I was very impressed and enlightened. One article specifically highlights games that are not time dependent. They do not depend on the users speed or coordination. I am not disabled, nor am I tremendously coordinated, but I found this site very cool.
Apple has been ahead of the curve on building accessibility into their devices.
On thing that happened when the 4s released that is disturbing. A app which did what Siri does was removed and disabled. I hope that Apple at least makes this available to the disabled community without having to buy a new 4s.