Telephone Poles - Great if you live in an area that still has them... Jog at a slow pace for 2 miles, then run at 80% between two poles. Slow jog to the next pole then pick it back up to 80%. Do 6 of these. Then sprint the last one. Slow jog home. Gradually build up (two poles, three poles, four poles, etc).
Track Laps: Pyramid workout. Run a 200m(half way around the track) jog for 200m, run 400m (once around the track) jog 400m, run 800m (twice around the track) jog 800m, run 400m, jog 400m, run 200m, jog 200m. Die. If you're feeling spunky still, get on the football field and do a 100yd sprint, a 50 yard sprint, and a 20 yard sprint.
Donkey Kongs: Find a multi-level parking garage with two stairwells. Run up first flight of stairs, run across the first level to the far stairway, sprint up the stairs, jog across the parking lot to the other stairway repeat till you get to the top - return down the same staircase to the ground level - repeat till legs are in agony. For the first go around on a 4-level parking structure shoot for 5. Gradually increase by one set as quickly as possible.
Suicides: Used by basketball coaches to weed out players and build up endurance. On a basketball court, start at the baseline (underneath the basket). Sprint to the foul-line, touch it, return to the baseline. Without stopping, sprint to the half-court line, touch it, return to the baseline. Sprint to the far foul-line (75% of the court's length) touch, return. Sprint to the far baseline, touch the line, and return. That's one. Complete 4.
Suicides can also be done on soccer fields (replace foul-line with the 18 yard penalty box), football fields, and even in parking lots.
Holy Sh*ts: Anerobic conditioning at its most miserable. These are simple. Pyramid-based. You run as fast as you can for 30 seconds. 1 minute. 1:30. 2 minutes. Then back down- 1:30, 1 minute, 30 seconds for seven total sprints. As you improve, and your lactic threshold increases, work up to 4 minutes. It's hell, but it teaches your body to function without oxygen. Do a warm-up jog for 10-15 minutes before starting the sprints. Then finish the workout with another 10-15 minute cool down jog.
Push-Up Run: This is a "fun-run." Lots of hotshot crews like to do "Ball-Runs." Twenty guys run in a line while a basketball is passed back down the line. When the last guy catches the ball, he must sprint to the front of the line. If anybody drops the ball, the crew gets down for 20 pushups. Sadistic Captains have been known to intentionally drop balls quite often. Simulate this training run by incorporating sets of twenty push-ups in between sprints on Hill workouts, Holy Shits, Suicides, Donkey Kongs, and Telephone Laps. Misery? You bet. Will it make you stronger? Damn right.