Is your power is out, your phone will be good for only a few hours of Angry Birds. You'll have to MacGyver a solution. The King of Random developed this tool to do the job. That's a salad fork threaded into a mixing beater inserted into a cordless drill. Connect your phone's charging cable to the battery terminals inside the drill. Then start turning the fork.
It may take a while. Suggestion: livetweet the experience to relieve your boredom.