Long Run with Tempo Finish: Run two-thirds of your long run mileage at an easy pace, then run the last third of your run at tempo effort.
Speed Play: Run the first half of your long run at an easy pace, then run the second half of your long run at 10-15 seconds per mile faster than you ran the first half.
Progression Run: Divide your run up into thirds. Run the first third of the run at an easy pace, run the second third of your run at goal race pace, run the last third of your run at 10-15 seconds per mile faster than your goal race pace.