Piggyback off of one of these church events with a side bet of sorts: if the group can raise the money on top of their normal sales in an hour, you'll shave your head.
I'm not kidding. My wife's old Latin teacher did this once, at one of their Latin Club functions; if the students could raise $500 in one hour for the club -note that this was completely spur-of-the-moment; there was no advance warning at all- he'd shave his head. They got over $1000 within the time limit. He did it the next year (this time the bet was that he'd have to dye his beard blue), and once again they got the money.
Granted, this isn't very amusing to watch while the money is being raised, but that's not the point. The point is after the money has been raised. I'm assuming the people at this church know you; if they don't then this won't work.
I'm not kidding. My wife's old Latin teacher did this once, at one of their Latin Club functions; if the students could raise $500 in one hour for the club -note that this was completely spur-of-the-moment; there was no advance warning at all- he'd shave his head. They got over $1000 within the time limit. He did it the next year (this time the bet was that he'd have to dye his beard blue), and once again they got the money.
Granted, this isn't very amusing to watch while the money is being raised, but that's not the point. The point is after the money has been raised. I'm assuming the people at this church know you; if they don't then this won't work.