Try this from the interpreter (after creating a window)

while True:
print pygame.event.wait()

to see all the events a window typically recieves.

For a program run from a file, even if it doesn't do any event processing, the window's lifetime will be so short that it probably won't have a chance for any unprocessed events to pile up. So that...

If I've understood correctly, flip() is specifically for double-buffered surfaces ... or more specifically, for changing buffers on surfaces for which you're taking advantage of SDL double buffering...

Just typing at the interpreter so far, but I'll try loading a file. BRB.

[Edit]
Okay, it works. This seems a bit off to me; if I call the update() function it ought to do what it's supposed to,...

(Google turned up this thread for me...)

Same problem. I've tried it by typing right into Python, from the Windows shell (cmd.exe) and from a Cygwin bash shell, and got slightly different behavior...