I remember reading a (parody, I think) story a few years ago about a set up for Rapture-worried Christians to leave messages to their less devout loved ones, reassuring them after the Christians were raptured. Those in charge of passing on the message would guarrantee that they themselves would not be raptured by "blaspheming the holy spirit" or something of that nature. People have been trying to get some post-apocalypse deals for some time (someone even saught ways of ensuring that taboos over nuclear wastes would survive a civilization collapse). But the Christians above at least knew the nature of the Rapture; to get a sensible bet on the singularity, you´de have to know a lot more about the post-singularity world than is generally allowed. It sounds likely that gold will be valueless after the singularity - but we can construct scenarios, not TOOO unplausible sounding, that would end up in gold being increadibly valuble after a singularity. I feel it is ignorance not of the date, but of the nature of the singularity, that is the true barrier to sensible betting on it.