Use the small, flat cones that are used for markers in soccer or hockey practice. Split the group up into two teams, making one team "domes" and one team "bowls." Spread the cones across a large area; the larger the area, the harder the conditioning. Put down one half of the cones pointed end up to make domes, and the other upside down to make bowls. Teams must rush around and turn all the cones in their opposite ends, with the dome team trying to create domes and the bowl team doing the opposite. Make the rounds 5 minutes long, counting the two types of cones at the end of each round. The team with the most cones claimed is the winner. Some rounds can involve running only, while others should involve wheelbarrow racing, walking in the crab position and riding on a partner's shoulders.
This game works best with a very large group -- 20 people at least, though the more people you have, the better. Split the group into teams of five or more and have each group form a conga line. Tuck a shirt or towel into the waistband of the person at the back of the line and then begin the game. The teams must stay within a certain area and must maintain contact between members in the conga line at all times. The person at the front of the group must try to snatch the "tail" from the waistband of the person at the end of the other groups' lines, all the while evading other groups to keep the tail. Once a group has lost its tail, it is out for that round. The last group with it's tail is the winning team.
Play tag within a specified area, with one person evading capture and the remaining players on the chase. When the chaser, or "it," touches an evader the person must freeze in place but can be freed when another evader performs a certain action. You make this any action you like, such as leaping over the frozen person or any other exercise. Chasing games of this sort have the advantage of building the kind of explosive speed and agility required by most sports.
You will need a lake, river or swimming pool with a long stretch of water shallow enough to stand in. A depth between waist and chest level is perfect. Break the group into two teams and have them line up, one in front of the other with hands on the shoulders of the person in front. When the game starts, the person at the back of the line has to swim down one side of the line to the front, run back through the water up the other side of the line and then swim under, through the legs of the rest of the team to the front of the line. At this point, the person who is now at the back of the line must do the same. In this way the groups will move gradually forward. Set a start and finish line. The first group to reach the end wins the game.