I've always thought that prisoners should be made to work to support themselves and others. Maybe the Chinese have hit on something with this:
"Prison bosses made more money forcing inmates to play games than they do forcing people to do manual labour," Liu told the Guardian. "There were 300 prisoners forced to play games. We worked 12-hour shifts in the camp. I heard them say they could earn 5,000-6,000rmb [£470-570] a day. We didn't see any of the money. The computers were never turned off."
The Guardian says that prisoners were beaten if they couldn't make their quota so maybe they're taking it too far, but the idea itself is still sound.