Just had an idea after watching a show called Ultimate Soldier Challenge. Here's the general idea:
People group up into squads. Depending on the number of squads present: 2-3 teams race from the same start line to separate but equally challenging objective points, eliminate equal number of defending enemy units that are pre-posted at their site in whatever fashion they deem most suitable; retrieve intel, personel, equipment, or whatever the event organizers can think up to enhance the game experience and race back to the same finish line and whoever gets back first with the fewest losses and the most objective items/personel wins. Feel free to review and reply with any idea that enhance the game's experience or fix possible unforeseen issues that I haven't taken the time to look into. This scenario is most effective with larger groups as are many airsoft game types.