Are you asking for Cathe workouts or any workout? When the weather is nice here I love to go to the local college stadium and run stairs. What I do is run up/down for 5 minutes, then jump rope for 3 minutes and keep doing those intervals for 30 minutes. I finish by running a lap around the field as fast as I can. I am itching to get my jump rope out I am a maniac for stairs!
Another good leg workout is plain ole jumping rope. It is amazing that so few kids do not jump rope at recess these days. Back in the olden days...we had the big two/three person ropes and we had a pack of girls who would spend every recess jumping ropes and seeing who could do the most tricky moves before getting tangled up! I have one of those big ropes and I do jump roping with my three DD's.
Anyone watch the jump rope competition's when they're on T.V.? I really enjoy watching those and seeing what kids come up with!!
Rollerblading is fantastic for the legs/tush too. Do intervals by changing leg position and also squating down low and kicking out to the sides. Just make sure you are making it a workout...push hard with your legs and really engage your muscles. Imagine yourself a speed skater and you're in a race, you need power and speed to get to the finish line. Too many people who rollerblade don't do it correctly for it to be a workout...they are merely roller skating at a leisurely pace.