IDLE is the Python IDE built with the tkinter GUI toolkit.
IDLE has the following features:
- coded in 100% pure Python, using the tkinter GUI toolkit
- cross-platform: works on Windows and Unix
- multi-window text editor with multiple undo, Python colorizing and many other features, e.g. smart indent and call tips
- Python shell window (a.k.a. interactive interpreter)
- debugger (not complete, but you can set breakpoints, view and step)