hehe, this is hilarious, while at the same time very ingenious. The Placebo Mini-pattern for long running processes.
Basically, it just estimates approximately how long said process might take (because you really have absolutely no idea). It then shows a progress bar (which sticks at 90% if not done yet). I think this is really great because it will pacify the user until it's done. And in the case that it stays at 90% for a while, well, then something's wrong anyways, but at least you got the user to wait that long ;-)
I'm researching a few things myself on long running process patterns. More info if and when I come up with it ;-)