Just thought I'd share this note. I did all the Halloween quests on the last day of the event and killed one of the Wickermen by Undercity which gives an experience and reputation buff called "Invocation of the Wickerman" (Horde can also get it, some less killy way I assume).

http://www.wowhead.com/?spell=24705

Had I known about it earlier I would have done a major rep grind for all Insane factions over the last two weeks with this buff up as much as possible. Nonetheless it was the day prior to getting exalted with Darkmoon, so I had it up while I turned in all my decks, which as human with an additional +10% +10% gave 420 per turn in, so I ended up with decks left over (can't complain lol).
Anyway, assuming the Insane title or other such rep grinds are still going next Halloween, I'd recommend planning a serious grind during this period for optimal rep gains.

Cheers, Peagle-Daggerspine

Peagle,

I am so sorry for the delayed response, life has been crazy for me lately. It annoys me that it took me this long to get this tip up. I havnt been keeping up on WoW lately, but I imagine the Halloween events are over. Hopefully this guide will be around for another year to help someone else with the grind. Let me know if you come up with anything else.

Thanks,
Callahan

Callahan -

Hey don't worry about it, I only noticed right at the end of the event, so it was more of a retrospective tip anyway.
That said it did inspire me to investigate if there were any more +rep buffs that could be utilized, and I located something coming this very Thanksgiving:

http://www.wowhead.com/?spell=61849
The Spirit of Sharing
Increases reputation gained by 10%. Lasts 1 hour.

It would appear that the new Pilgrim's Bounty holiday (2 weeks from now, 11/22 - 11/28) provides a +10% rep buff for sharing food in the capital cities. Don't know the specifics yet, however it would be another prime time to hand in decks or librams, or whatever grind you may be doing :)

Cheers Peagle