In the winter I do 8 x 1k with a 1min jog between, running on dirt or grass and aiming for around 10k race pace. In the summer I do 6 x 1k on the track with 1min walk between, aiming for 5k race pace.
3 sets of 5min threshold with 1 minute jog recovery, followed by 4 x 150m steep hill sprints with jog back recovery.
I like to mix hills in with some flat running to replicate cross country.
10 x 400m with 60s rest in-between reps
I remember the first time I ever did this session, it was a few year ago now at Olympic Park, trying to keep up with Mark Tucker, Richard Jeremiah and Collis Birmingham. They ran 60s or less for every rep, something I hope to do in training this season.