A Push-up is a body weighted exercises that can be done anywhere with numerous modifications. My favorite is the diamond push-up and the classsic push-up. You perform this exercise with high reps to make it an endurance or HIIT workout or slow it down and use it to build strength and size.
The pull-up is another one of my favorite bodyweighted exercises. This pulling Exercise worksout your back muscles including your lats and biceps. Like the push-ups you can do these just about anywhere to build strength and endurance.
A dip is another push exercise that can help build strength and size in the arms and chest.
Well there you have it. My top 3 favorite exercise to do when I am pressed for time or just want to get a quick workout in. So take my advice, go out there and push yourself!