Inchworm Push-Ups are a great total body exercise you can do anywhere!
To get started, stand up tall with the legs straight, and do let those fingertips hit the floor. Keeping the legs straight (but not locked!), slowly lower the torso toward the floor, and then walk the hands forward. Once in a push-up position, do a push-up and then start taking tiny steps so the feet meet the hands. Repeat this 4-8 times.