I don't have anything against weight lifting other than they cost money and I can't travel with them. I do, however, have a big problem with people who hock them these days. This could easily take up a post all it's own (and I might do that sooner or later) but if there's one thing that I want to zero in on right now it's that mentality that you can only exercise at a gym. I don't care if it's one that you have a membership to to or it's your own home gym, I do have a problem with that line of thinking. The basis for that complaint is simple: What if you can't make it to the gym? Are you screwed?
Not as far as I'm concerned. I operate on the, "don't give me problems, give me solutions," mentality. So, if I don't look at the problem thinking: I don't have a gym, I can't exercise. Instead, I think about how I can exercise even if I can't get to a gym. As I've previously stated, I travel a lot. So, I'm forced to exercise in places that aren't specifically set up to exercise.
Find a bare stretch of wall. What can you do with it to exercise? You could do some handstand pushups, a few wall walks, and some wall-chair isometrics. Maybe it doesn't hit specific groups of muscles but it works quite a few body parts. The arms, shoulders, back abs, glutes, hips, and thighs are worked with three exercises and just a wall.
Here's the ulitmate test of creative exercising: The airplane. Try some isometrics and self resistance exercises for the forearms and grip. Do some deep breathing exercises. Perhaps some powerflexes for the calves and the thighs. Turn the leiderman chest press into an isometric movement. Then, do some visualized resistance neck work. Just because you can barely move doesn't mean that you can't do anything.
Don't allow yourself to fall into the thinking that if you don't have a gym, weights, or machinery, you can't work out. You can't afford to. You need to develop a mindset that you can and will exercise, no matter what. This is what will keep you exercising long after others stop.