Divide all track and field athletes into 4 or 5 teams and run relays(include throwers, jumpers, EVERYBODY). When choosing teams, use the politically incorrect schoolyard method of having 4 captains picking the teams. Yes, some poor soul will be chosen last, but it is entertaining hearing the hoots, hollers and comments. Typically, the weightmen will be picked last, but they don't really care since they can beat the crap out of everybody else. It will do the runner's egos some good to be picked early.
For the actual relays, do a variety of races, such as:
1 lap per person
2 laps per person
1 lap, 2 laps, 1 lap, 2 laps, etc
1 lap, 2 laps, 3, 4 etc, depending on how many guys per team....let the team use strategy for who runs what leg, and they can do it in any order.
Use your imagination for other races.
Give a prize to the team that does the best overall.
This will end up being a pretty good workout, plus it will build team unity. You will have weightmen, sprinters and 2 milers on the same team cheering for each other. Normally they have nothing to do with each other.
Our team did this a few times in college, and it was a riot.