I will bet 500 karma that a funny picture thread will appear on Less Wrong within one year. If anyone is interested in the bet, we can better define terms.
Right now the LW software doesn't support karma transfers. Until it does and we can develop a more robust prediction market, let's just record the karma transfers on the wiki page that already exists for this purpose.
I will also give 100 karma to anyone that donates $10 to the SIAI before the current fundraising campaign is over.
10,000 karma for the first person with a karma transfer source code patch?
I think a standard one-way virtual economy approach would be ideal for this: Track users' "betting scores" separately from their karma, allow them to purchase score with karma, but not vice versa. Then lousy betters can blow their general reputation if they so choose, but a skilled better still needs to earn karma the "honest" way.