I have one I've tried only twice now(wish it was a bit warmer in the morning, damn old man winter) based around a rugby pitch,
4 laps of a rugby pitch steady state(warm up)
2 laps sprinting on 1 of the short sides, jog the others
2 laps sprinting on both short sides, jog the long ones
2 x 4 sets of Tabata sprints, jog to the 22m line and then spring the rest,
the Interval between the sprints I try and do 1 minute of very slow pushups(only get 6 or so in)