Some other thoughts:
110m target soak - athletes must run 110m while soaking targets spaced 10m apart; all targets must be hit; fastest time wins
110m stream dodge - similar to the 100m target soak, but instead of shooting at targets, targets fire at the runner (alternating high or low streams); athletes must avoid as many streams as possible; fastest time with least hits wins
100m single soak - athletes must sprint 100m with their soaker, then hit a target placed 10 meters away (on one side) from the end point; target being hit stops timer; fastest time wins
800m soaker relay - teams of four athletes run along a track, one at a time. Instead of passing a baton, they pass their soaker on; at the end, the final athlete must hit a target placed 10 meters away (on one side) from the end point; target being hit stops timer; fastest time wins
synchronized soaking?
