There's nothing wrong with sticking to the classics. This old favorite is easy to do on your bedroom floor.
- Lie on your back with your knees bent and your feet about 12 inches from your butt. Put your hands behind your ears.
- Focusing on your core muscles, lift your head and shoulders and raise up until your head, shoulders, and back are off the floor. Keep your belly button pulled in.
- Lower back down to complete one rep.