I've come across a revelation. A revelation, at least, to me. A couple of places on the intertubes have called it "The Brad Pitt Rule" and I think that's a pretty good name.
There was a girl in college. There was a girl in college in one of my classes. There was a girl in college in one of my classes that I often felt like walking out of. Instead, we'd pass the time talking quietly and jotting witty quips on our "notes."
I got to know her and thought something along the lines of "Hey, this is a pretty cool chick." I didn't throw myself out there much, but for some reason I did this time. I called her up and asked if she wanted to grab some coffee. She hemmed and hawed a bit and said that she'd love to, but she had to "go running." One of the things that we had in common was the fact that we both risked death by trying the Atkins low-carb diet. She had started running and had really gotten into it. I, on the other hand, had started napping and had really gotten into it.
I tried a couple more times and every time she had to "run." After the third time I started to catch on.
This is where the Brad Pitt Rule kicks in.
The Brad Pitt Rule states that if you ask a girl out and she says yes, then great, she probably likes you. If she gives an excuse, then you have to ask yourself, "What if it weren't me who asked her out? What if it were Brad Pitt? Would she still have to study, or hang out with friends, or run?"
Of course not.
She would have moved things around, made exceptions, rescheduled, done pretty much anything to go out on that date.
Brad Pitt himself isn't really relevant; it's what he represents. He represent what she wants.
If you are what she wants, she will drop her other plans to spend time with you. You make time for what your heart truly wants.
Of course, there are exceptions. She very well may have to work all night or need to study for her midterm that's in the morning. But if she's really into it, she'll be up for something some other time (and maybe even suggest it herself).
So if there's an excuse and nothing else is planned, she's just not into you.
Sorry.
Quit calling her.
Weirdo.