I have successfully used variables to suppress sections or for formatting purposes. Not sure if that's what you're looking for though.
Just state the variable as so:
global numbervar nVariable=
Seems like you're going to be limited as to what you can actually do with it, but you can use them outside of a formula field. Of course, you would still have to make a formula that contains the variable and it would have to have a value.
Edited by FrnhtGLI - 18 Feb 2010 at 1:45pm