Squats
Try air squats, side step squats, sumo squats, jump squats, and even weighted squats. You can even try holding a large bottle of detergent to get some added resistance with your squats, just make sure the lid is on tight.
Front lunges, back lunges, and even side-to-side lunges are an excellent exercise for targeting the large muscles of the lower body. For an advanced movement, try jump lunges to get your heart rate up.