Donation letter auctions each month. Perhaps a bulk auction at some point of many different donation letters from a couple of months. *shrugs*
Hold Giveaways during holiday times..or make up your own holidays to give stuff away at. One good time would be the anniversary of you getting your halo perhaps..seeing as this is the reason your thinger was created. Have a big random giveaway of gold, letters, items, etc.
Perhaps have a bunch of people sell themselves out as bumpers. Half the profits go to the chairty or something like that?
Lets see...hurm...ask people what their talents are of those you've gathered in the thread and see if they'll offer some of their services for a charity raffle.
And as far as fat chicks getting Owa for cash...*digs out wallet* I could pay for a couple of rounds ^__~ <3.