Me and James have always shared a room, (we all double and now triple up) and cleaning it was always a couple day job. We couldn't be bothered to keep it clean, nor get it clean quickly when told to. So our parents would say no eating until it's done. Which, like other punishments, encouraged us to steal some food. So we'd grab handfuls of chex cereal and store in in a small plastic case that was meant for plastic knights. We weren't even starving, it was just a snack to 'tide us over'.
Another thing we'd do is make cleaning our room a game. The goal was to not touch the floor, which of course got more interesting the further along we got. It took us forever, but cleaning our room was always loads of fun in the end.