This is a paintball scenario, also known as "Assassin." One player is designated as the assassin, while another poor sap is the president (or VIP, whatever terminology you want to use). Several guards (ideally 3 to 4) must escort the president down a predetermined path, trying to keep him/her from getting hit. The real kicker: the president can't carry a marker! This makes it hard to get a volunteer. For more variety, limit the amount of paint the guards can carry. Twenty rounds is a good number. If you like the loner aspect of the scenario, try downed pilot, too.