I have my gym bag packed and I'm going to bring it with me to work every day so that I'm prepared if the mood strikes me to pop over. I'm also being very careful not to set unrealistic goals for myself (i.e. - trying to work out every day or for really long amounts of time). I figure if I even get in once or twice a week to start with, I'm doing well. As I get into it, I'm hoping that I'll be inclined to do more. We shall see.
Edit: I forgot to add that I was really nervous about telling Jboy about the gym when I got home last night. I was afraid that he'd think it was silly to spend so much money on a gym. When he got home, I told him that I'd done something crazy. When he asked what, I told him that I bought a new bag (I have a collection of backpacks that just seems to keep growing). I brought out the bag to show him and he saw that it was Good Life gym bag and rather excitedly stated "You joined a gym!" The reaction was so positive that it almost surprised me! Here I was all nervous about people thinking I was wasting my money and instead I get this response of how it's an investment in my health and total support! It was wonderful and made me feel so much better about my decision.