What kind of exercises can you do from home that don't involve using weights so that you can get a bigger butt and bigger and stronger thighs and calves?

Do squats without weights, kept the reps up until you can feel your glutes and thigh muscles working. The more upright you are, the more you are working your thighs. The more you tilt your upper body ahead, the more you are working your butt. You will feel the difference. Do about six sets of as many as you can do. Do this every three days giving your muscels a chance to recover. The best exercice I find is being in a lung position but not returning to a standing up position, just keep squating on one leg until you feel your buns burn, then do the other leg. If you have trouble balancing, you can place one hand on a chair, but only for balance, keep the weight on your upper leg and glute. Calve are easy, just do calve raises on a step in the house.