Burpees Exercise - The greatest!
This is an amalgamation of a squat and a squat thrust. Stand straight, bend your knees and put your hands on the floor, kick your legs back until you are in a pressup position, then bring your knees back in and stand up again.
This is the best lowerbody exercise invented, I cannot recommend it highly enough. If you want to get the most out of it I would advise you do 1 pressup while in the pressup position and while standing up jump a few inches off the floor.
I would recommend doing a press up with every rep when you are in the correct position (also called b*****rds on account of how taxing they are!)