I've been shooting a fight scene today set in a nightclub. As well as the two protagonists and a couple of bystanders who get involved, I needed a whole bunch of extras. There's a band, a couple of bouncers, and a load of clubbers, some sitting around, some drinking, and some dancing. For the first time, I found myself wishing I was shooting in an MMOG instead of using a script-based machinima tool. It would be so much easier to find 30 people, tell them what I want them to do, and let them run their dance animations. Instead, I'm having to script every one of those extras myself. Setting up the basic actions takes quite a lot of time, but then having to put all the reactions in and get all of them rushing for the door is really time-consuming, and really tedious.
One way of looking at it is that if I were to shoot the scene with lots of people, it would probably take three or four hours to get it right. That's 100+ man-hours. And if I later decide to reshoot, that would be a logistical nightmare, and I don't even want to think of the continuity problems. This way it'll take me a couple of solid days to get the scene, which is way fewer man-hours all told, and I know I can come back and tweak the lighting and the cameras later if I need to.
But that doesn't stop me wanting a tool for controlling crowds and some AI for my extras so I can get the whole scene done in half the time. Then maybe I can realistically aim for getting real crowds like this...

Hmmm... maybe I should hack
Total War and change the soldiers into nightclubbers and turn their combat animations into dance animations... on second thoughts, maybe not! It's a damn shame the rumours a few years back of a
freeware version of Massive never came to anything. It's
rather too expensive for me.