Hey Paul J, you wanna do exercises that involve jumping. Here are some good ones..
1.) Jump rope
2.) Box jumps (find a stable box or chair, and jump onto it. Then as you're on it, immediately jump off of it). Do this 15 times to complete a set. Do about 4-5 sets a day. And rest about a minute between sets.
3.) Knee jumps (basically what you do is bring your knees close to your chest by jumping as high as you can). Do this 20 times to complete a set and 2 sets a day. Rest for 2 minutes between sets.
4.) Play basketball