This week spice up the speed work by varying the distance for the hard interval. Start with a nice warm-up and then follow the format below.
200 meters fast, 200 meter recovery
400 meters fast, 400 meter recovery
800 meters fast, 800 meters recovery
Then, climb back down the ladder (800, 400, 200).
Depending on ability level and race goals you can start on a higher rung of the ladder. For example, 400m, 800m, 1 mile. Strive for faster intervals on the climb down than on the way up.