For each nonland permanent, choose a player at random. Then each player gains control of each permanent for which they were chosen. Untap those permanents.
9/22/2011 Once Scrambleverse starts to resolve, no player may respond until it has finished resolving. For example, you can’t wait to see who will control a creature before deciding whether or not to activate one of its abilities.
9/22/2011 For each nonland permanent, any player may be randomly chosen, including the permanent’s current controller.
9/22/2011 All of the control-change effects happen at the same time.
9/22/2011 Each nonland permanent will untap, no matter which player was randomly chosen to gain control of it.