I just posted a little while back that the Darkmoon Faire needed a change, but apparently there's still some benefit to be had over there -- Valdesta of WoWGrrl has found at least one way to keep the Faire interesting. She's been keeping a character over there, apparently, and periodically checking in on what the vendors have. They sell not only little pets and miscellaneous items like the Heavy Leather Ball (which often sell for a tidy profit on the AH, since people aren't always aware that the Faire vendors sell them), but there are also vendors there who sell profession items like herbs, motes, eternals, leathers, and so on.
And as anyone who's ever levelled a profession knows, those are often worth their weight in gold, not just on the AH, but in terms of leveling up your own alt professions as well. As Valdesta says, it's worth camping an alt over there just to check in during raiding downtime or on a flight path with your other character, for the same reason you should always check and see just what other vendors around the world might have for sale -- sure, you won't make much with just one buy, but over time, picking up cheap crafting mats from the DF can lead to some solid profits on the AH.