Hindu pushups are great for including more of your upper body into the exercise. These variations are fun and provide a great stretch as well.
Start in standard pushup formation. Bring your feet in towards your head while keeping your legs straight. You should be forming a triangle with the floor. As you lower yourself to the floor, bend your elbows, continue to keep your legs straight. Bend your spine as you look up and feel the stretch! Slide back to pushup formation and repeat.