You get bigger faster by lifting weights and eating right (far more so than push ups). Eating is so very important. Compound lifts = good.

On a side note, here is a link to an article talking about how Hollywood actors gain muscle quickly for movies. It's from two guys that train these people to gain as much muscle as possible in a 12 week time frame. I thought it was really interesting.


http://www.t-nation.com/readTopic.do?id=917176