Often I get asked questions like "I don't want to join a gym, but what else can I do besides running?" or "How can I spice up my workouts without having access to equipment?"
I'm a big fan of plyometric bodyweight drills due to my time running track in high school and college. (note - I was not very good and probably lost 99% of my heats) I use bodyweight plyos as warm-up drills for most of my fitness classes, and also as a form of Tabatas to get everyone's heart rate elevated and make them earn their trip to the water fountain.
Plyo drills are a great way to not only challenge your cardiovascular system, but build your explosive lower body power and fast-twitch muscle fibers. These drills can be difficult to explain and are best demonstrated - so I've decided to use a pretty accomplished source as an example, IFBB Figure Pro Erin Stern.
Erin Stern is the 2010 Ms. Figure Olympia, and competed in the high jump and heptathlon at the University of Florida. I'm always biased towards track & field athletes, and Erin Stern justifies my feelings with how well she hits each of these drills shown in the below videos.
Erin Stern is one example of why it takes a lot more than just "going for a jog" or reading a magazine on the StairMaster to achieve the sort of physique you can be proud of.