I've been meaning to go to the gym, really. I just haven't had time lately. Now that my schedule is starting to smooth out again, my intention is to start lifting weights. I get more than enough cardio elsewhere, as I ride my bicycle as my primary mode of transportation, and there is nothing I love more than sprinting home. Of course, my gym is the university rec center, so it's a bit different than a normal gym. It's really too big to make friends at the gym; however, I do run into people I know there.
When I was using the gym on a more regular basis, I would eat a banana beforehand and drink a small container of chocolate milk afterward. I also often worked in a casual swim in the deep well to stretch out all of my muscles, followed by a brief session in the sauna. That's the real reason to go to the gym in my opinion--the pool and sauna. The ab and yoga classes are also a plus. I'm planning on taking some yoga through the rec center this fall, as it's cheaper than yoga classes for credit.
I definitely listen to my own music. On my iPod, I have a playlist titled "Ninja Training Music" just for workouts.
And yes, genuinegirly, a good poop is essential before any heavy workout, especially running.