Here's a short VI to show how to do it. The trick is setting the mechanical action of the pushbutton. The only thing to remember is that the switch will only have an effect when it's read, so if the loop takes 2 seconds to execute, the switch will only be read every 2 seconds.
One way around this is situation to put the button and its display in a seperate loop that passes its state to the main loop through a global. This way the text will appear right away and the global can cause the main loop to pause until the button is released. See example 2.
Mike...