tried to write a wikiHow article for an astronomy software tutorial. check back to see if that can work.
also spent a decent fraction of my time looking into archiving wiki content through mirroring, XML source dumps (damn you Trac), etc.
finally, even though a wiki produces pure web content with simple editing tools, complete source packaging, detailed revision control mechanisms (throw in the social web connections if you like that sort of thing) it gonna be a haul to convince...