I try to exercise on a regular basis too. Of course I don't always want to. The thing that works for me is to just DO it. I don't give myself time to think about it, I just jump right into it without a second thought (before I talk myself out of it!) and before I know it, I'm feeling so good that I actually want to keep going until I finish!
The trampoline thing sounds fun!
Love,
Sujin