Common expression used when faced with once friends or with someone you just used for something and feel like you need to make it up to them by hanging out or doing something with them sometime. In reality, this 'something' will most likely not happen anytime.
Oh wow! I haven't seen you in a while. How are you? GOOD! well, I gotta go, but we should do something sometime! can't forget the *wince* Call me!
a vague-ity, but with positive intent. Saying this allows you to test the water, but is sufficiently vague to allow you to maintain a sense of detachment from the question.