Straight from the "Things that could have been" department, No Mutants Allowed have asked their former BIS contacts to kick the dead Van Buren horse one more time, which has resulted in them getting their greasy hands on the Van Buren tech demo code. In case you're wondering, Van Buren was Black Isle Studios' last attempt at making Fallout 3 before licensing (and subsequently selling) the IP to Bethesda.

Go here for more info.
Since this is a pre-alpha thingamajig, don't expect a lot in terms of gameplay or stability. In fact, I wouldn't recommend torturing yourself by downloading it at all, but I'm going to anyway.
NMA requests that other sites wait a couple of days before mirroring this file. However, since the 3DDownloads waiting queue seems to be around 20 minutes now, you may want to ask around on IRC to see if anyone can hook you up.

If you're in line waiting, here's some more Van Buren to depress you:
Video (low-res YouTube link is your best bet)[/url]
Screenies

Thanks Kotario and Brother None (formerly known as Kharn) for pointing this out.