Actually, I'm surprised Mark doesn't remember (or maybe he just didn't want to get bogged down in details)-- he paid for my lunch, and I paid him back in Bitcoins.
Which turned out to be a good deal for him, they went from about 40cents apiece to something like 60cents apiece in the week or so it took him to setup a bitcoin account and give me his receiving address (I paid at the 'when we had lunch' exchange rate, of course).
If you have a bitcoin business and are thinking about advertising, FTL listeners might be a receptive market-- and I bet you might be able to convince Mark and Ian to take payment in bitcoin.