Start at the Pillars. Run 3 x 750m (on 4.15), finishing the third rep at the 750m marker. Walk to the bottom of Anderson St then run 8 x 100m hills (with easy jog down). After last hill rep continue easy jog to the 750m marker and run one final 750m back to the Pillars. 
Option: shorten distance of each hill rep if you wish.

Use the 'bottom of the tan', starting clockwise from the Pillars. Run two reps out then two reps back and regroup at the Pillars before the next set of four. Although the reps are quite short so is the recovery- so this is a tough session. 
Option (middle-distance): you can make this session much more intense by skipping the middle 2 or 4 reps. So 2 x 4-5 x 75 secs (with a long SR in the middle).

Meet at the Pillars and then walk across the road and start on the bottom trail next to the river. Run towards Richmond, turning around after 4 reps. 
It can also be run as a steady/easy continuous run.

A new club championship event. 4 x 1km on the track at AOP. Teams of two (two legs per runner).

Middle-distance option: for a faster-paced session run every even rep as a 500m (still on 5.15). So alternate 1000's with 500's...