pyratemp is probably (one of) the smallest complete template-engines for Python (with about 500 LOC). It has a very small set of special syntax in the templates. This reduces complexity and the probability of bugs and lead to an easy-to-use and intuitive user-interface. It uses embedded Python-expressions (in a "sandbox"), is well documented, has full Unicode-support, and produces very good error-messages, which is very useful when creating new templates.
Urwid is a Python library for making text console applications. It has many features including fluid interface resizing, support for UTF-8 and CJK encodings, standard and custom text layout modes, simple markup for setting text attributes, and a powerful, dynamic list box that handles a mix of widget types. It is flexible, modular, and leaves the developer in control.
Flightdeck-UI is a project that utilizes the ideas in the design of aircraft controls and instruments for creating general purpose user interfaces. The project includes Flightdeck-UI Online (a Web-based monitoring system that works entirely through the browser), the Multi-Variable Monitor (MVM) application, and a Tkinter widget library. Flightdeck-UI Online is installed on a Web server. The MVM application provides a graphical editor with theme support for quickly creating Flightdeck-UI control panels. It is possible but not necessary to write code in order to use MVM.
Webwidgets is a framework for writing Web applications as if they were desktop applications. It employs the same programming paradigm as GTK, Qt, etc. with a tree of widgets with callbacks for events such as a button press. It encapsulates page loads, session data, form handling, etc. into widgets with their own state. Webwidgets is focused on code reuse, rapid prototyping, and separation between graphic design, interaction design, and application logic. It is implemented in Python and uses the Webware application server framework.
Squires is a Python library which simplifies the creation of powerful self-documenting readline-based command line interfaces. Scripts using Squires have the following features in their interface: full readline bindings, tab completion of commands and their options, inline command help (which is accessed by pressing tab), option syntax validation, and hidden commands and options.
Wimpiggy is a library for writing EWMH-compliant, compositing window managers using Python and GTK+. The goal is to make writing a window manager as easy as writing a PyGTK application. This library can be used to build a trivial, working window manager in only about 40 lines of code.
Peggy helps you to create GTK applications that run out-of-the-egg. It offers functions to load resources (like .glade files, images, and locales) from a zipped or unzipped egg. It is a thin layer on top of setuptools and PyGtk. It doesn't do anything very fancy, but it can save you from reading some documentation.