Here's an article that I read a little while ago, and I always like to include celeb articles here, so we can contrast the different methods of working out for different purposes. (-2 Points for run-on sentence intro).
"After [the first routine], Robert felt kind of bored with it and wanted to something a little more exciting... so we decided to do what I call a Rocky IV meets high-tech training," says Bose, who bulked Downey Jr. up to 175 pounds over the first three to four weeks filming.[ More @ Yahoo ]
Examples: "Instead of doing regular bench presses, we used a bamboo bar... and we would hang plates on rubber bands off the bar... so it was like trying to bench press a snake!" Bose explains. "It bounced all over the place."