The first effect tries to mimick the animated thingy on
the upper-left corner of the window in Mozilla
(probably could still use some tweaking):
http://www.ualberta.ca/~cwant/gimp/transitions/TransMozilla.pl
http://www.ualberta.ca/~cwant/gimp/transitions/TransMozilla.mpg
The second effect, writen by Guillermo S. Romero, has to be seen to be believed!
http://www.ualberta.ca/~cwant/gimp/transitions/TransEatTheFilm.pl
http://www.ualberta.ca/~cwant/gimp/transitions/TransEatTheFilm.mpg
Chris
nice! I’ve only used the gimp for still images. I’m not sure how You do these transitions. Is there a tutorial or site that explains? (pardon my laziness- perhaps I should just look)
Edit:
Your poll is not calculated to elicit responces, now, is it? 
There isn’t much out there in terms of documentation – this is kinda
new ground. I do discuss the setup and usage of this framework
in more detail in this thread:
https://blenderartists.org/board/viewtopic.php?t=427&highlight=
I plan to have a web page up soon with even more details.
Two people have responded “Of course – what a dumb question!” …
I better set up a paypal account, pronto! 8)
Chris
Two people have responded “Of course – what a dumb question!” …
make that 5 persons 
Martin
Holy smokes! That’s unreal… Done in Blender as well, I presume?