I get bored really easily, so I make up things to keep myself interested. Here are some of the other things I've tried as "interval training" in the past couple of years.
14 is a lucky number.
Sprint up stairwell of 7-10 floors.
Go down decently quickly. Every other floor on the way down, 14 squat jumps, or 14 split jumps, or 14 lat pull-ups hanging from the handrail bar (ymmv, my stairwell is configured in such a way as to make this possible).
Substitute stadium steps if you're lucky enough to have access to those. More and more big stadiums seem to be locked at night these days, the bastards.
(with a jump rope)
28 seconds regular jumping
28 seconds double-unders
28 seconds regular jumping with crossovers
14 seconds triple-unders (sweet jesus this is hard)
Take a jump rope. Learn to do percussion with your feet and the rope. Alternate between slower rhythms (= low intensity) and faster rhythms (= high intensity).
Bonus, you will achieve instant hero status if there are any sixth-graders around.
Bonus number two, this is a hell of a lot less boring than any other form of training I can think of.
Jog along the street. Snatch purse from elderly woman. Sprint. After 20 seconds, hand purse off to unsuspecting fellow pedestrian. Run away at 70-80% intensity. See cops again. Sprint.
Well, at least #1-3 are good.