Pushups can be varied in many different positions to hit many different muscles...
Doing standard pushups with a ultra-wide grip will hit your pecs hard and your front delts too. You can do half reps to make it really burn...
Moving your pushoff point (where your hands meet the ground relative to your body) can make a big difference as well. To burn out you can position your hands near where your stomach would contact the ground.
Another fav of mine is to put each hand on a raised part of the ground (on top of two objects at the same height). That way, when you go down, you can REALLY lower your body beyond what you normally would because the ground would have gotten in the way. It REALLY burns the chest
And diamond pushups really burn up the forearms
While getting ready for the military, I do pretty much pushups, situps, pullups of all kinds of variety... and throw in ass-to-grass squats, deadlifts, and barbell rows in to work out the rest of my body. That and run and run

Suprisingly, I'm not losing weight, but gaining definition.... your mileage may vary though