This kind of problem is usually due to a command being run in one of bash's initialization files that never finishes so a prompt is never shown.
In OSX, the likeliest culprit is
$HOME/.bash_profile. The simplest solution is to rename it and open a new shell. If that works, you can go back and copy anything you need from the original file. If you do this carefully, you should be able to pin point the original problem.
In this particular case, the problem is this line in
The result of this is that
.bash_profile will read itself over and over again in an infinite loop. Deleting that line will fix the problem.