This is a minimal python plugin for GIMP. In contrary to gimpfu-based ones, these do have the functions also available in C plugins (query, init, run, quit) and can (actually, have to) use GTK+ directly to create a user interface.
I've attached an minimal-really.py plugin, which does only define what is needed for a plugin (query, and the functions to be used). 99% of all python plug-ins will most likely follow this structure.
The more complete minimal-real.py defines all things that you might want to redefine in your plugin.
Yes, you could do even more and redefine start(), which would enable you to change what is actually regarded as init, query, quit and run). And you could have your own run() as well. It's just that right now, I can't imagine why anyone would want to do this. But maybe there are some clever ideas?