cardiovascular conditioning ideas

Can anyone suggest some good cardiovascular workouts that do not involve prolonged aerobic endurance activities? Basically I’m looking for some interval or windsprint schemes that will provide cardiovascular benefit.

If you have access to a 400m track, the best thing I did in the offseason for cardio were ‘hollow laps’.
Walk 100m (around the bend)
Sprint 100m (down the back straight)
Jog 100m (around the bend)
Sprint 100m (down the home straight)
3 laps equals 1 set

I did 2 sets with a 8 minute rest in between and I could swear that the next week at training I was fitter. I wasn’t very fit to start with so i really noticed the improvement

It’s also good practice for keeping your form and staying relaxed when you are fatigued.

Is this just for general fitness? If so, you can still do tempo work (just at elevated levels), even in the pool. What about cycling? It really depends on what and who it is for.