Well, I'll throw my hat into the ring, here.
I'm by no means an expert on any given subject, but its nothing some extra reading can't fix.
I'm a filmmaker so, I'm trained on the subject (storytelling, editing systems, film stock, camera equipment, sound equipment, film theory, lighting, screenwriting and film history).
Under that blanket is also a familiarity with various sorts of cinima: wuxia, documentary, action, etc.
Also, my roommate is also a filmmaker, so any gaps in my personal knowledge/experience, he can help fill in.
I've researched a number of smaller topics, usually specific time periods or historical battles. Some of these things are:
- Dinosaurs. I read a lot about them as a child, so my knowledge of current breakthroughs is limited.
- Ancient Chinese history, specifically the Three Kingdoms Period. I could talk your ear off about that one, in the context of Luo Guanzhong's "Romance of the Three Kingdoms"
- The Battle of Bannockburn, the battle where Robert the Bruce led the Scottish Rebels against Edward II and won, while outnumbered at least 10 to 1
- The Battle of Thermopolae (sp?). Yes, I've read up on it more than just what 300 shows.
- The 2nd Crusade. I don't know as much as I'd like about this and I'd have to look a lot of it up again.
- Norse Mythology
- Greek Mythology
- Art History. Its been a few years, so I don't remember everything from my classes.
- Star Wars. Yeah, that's a setting I know a lot about, though I've sortof given up on the novels since the Yuzan Vong were introduced.
There's also a variety of tidbits of information floating around my head, so I can probably add a little bit here and there to other topics.
I also have access to some friends who are fonts of knowledge as well.
One friend knows a lot about the Sengoku Jidai era of feudal Japan.
The other friend... well... he just knows a lot. As an example, he was able to totally justify, with available technology, constructing a long-barrel rifle with precussion caps and some other stuff I don't remember, in a GURPS setting with the tech level being... um... I think at best there were bronze cannons.
I hope I can contribute in a meaningful way.