Anyone else jump rope for cardio?

I bought an $8 jump rope off e-bay like 3-4 years ago and it's still going strong, it's just a thin metal wire with metal handles, bonus if you mess up it slaps you I had marks all over my arm until I got better.

I go for at least 20 minutes but I try to go really hard, I lift my knees up high like I'm doing high knees (I jump from one leg to the other one at a time). If you do that fast enough it's great cardio, balance, etc., and takes very little space as long as your ceiling is high enough.
Would kick em in the nuts