There are numerous ways to keep score in an activity. One way is the "Cliff of death". You draw a hill, that turns into a cliff, on the blackboard. At the bottom of the cliff is an ocean full of sharks. Mark the hill (leading up to the cliff) with lines to mark the different points of progress. Using markers to represent the different team, the markers slowly get to the edge of the cliff as the team answers incorrectly, or another team answers. When the marker goes past the last position, they fall into the ocean and die a horrible death. Correct answers move the markers to safety.
Use pictures of students/teachers/famous people for the markers. A picture of a teacher's head on a stick man can go down well. Laminate and stick magnets on the back to make the markers last.
When two teams are involved, each team's goal is for their stick-man to be drawn. They start with a head (and never have less than that). When one team scores a point, they get a knew part to their stick-man if and only if the other team has no parts on their stick-man. If the other team does have a part, then one part is erased. Make the stick-man more evolved for a longer game.
When first explaining this activity to the students simply draw the stages along the top of the blackboard (ie, just a head, then a head an a torso, then a head, torso and arm, etc), with arrows between the stages (a plus for adding and a minus for subtracting).
See Genki English for some more ideas:
See more information about how to get started at the Central Wikia tutorial.