Verb: to utilize any and all objects around you in order to do something slightly useful, but more especially, just damned cool.
1. "You locked my keys in the car! Well, do you have a piece of gum? We're just going to have to MacGyver our way in and get them."
2. "So we're going to die in a nuclear explosion! Well do you have a Zippo and some gum? Let's MacGyver ourselves a spaceship.
3. "So we're in Hell! Well, do you have a Zippo, a piece of gum, and a shoestring? We're just going to have to MacGyver our way back to Earth.