easygui is a module for very simple, very easy GUI programming
in Python.
Experienced Pythonistas need support for quick and dirty GUI features.
New Python programmers need GUI capabilities that don't require any
knowledge of Tkinter, frames, widgets, callbacks or lambda. This is
what easygui provides. Using it, all GUI interactions are invoked
by simple function calls. 

easygui is different from other GUIs in that it is NOT event-driven.
It allows you to program in a traditional linear fashion, and to put up
dialogs for simple input and output when you need to. If you have not yet
learned the event-driven paradigm for GUI programming, easygui will
allow you to be productive with very basic tasks immediately. Later, if you
wish to make the transition to an event-driven GUI paradigm, you can move
to an event-driven style with a more powerful GUI package such as anygui,
PythonCard, Tkinter, wxPython, etc.
easygui is there just to do very basic stuff. More elaborate stuff should
be done with more powerful tools. easygui is built on top of Tkinter.

A tutorial and more complete documentation can be found on easygui homepage.