Over at Intrade.com, traders can bet whether a US health care plan with a public option will be signed into law before the end of the year. It has actually been one of the more actively traded contracts on Intrade with 2,706 contracts already changing hands. Over the last two days, the odds based on the contract price have dropped from 45% to 25%. Interestingly, the odds stayed stable between 45% and 50% last week and through the weekend, even as a number of issues arose that signaled a delay. The drop didn't start until yesterday when word got out that the Senate Finance Committee was working on a plan that scrapped the public option altogether. It seems that up until yesterday, people thought that the public option would most likely happen, but they just didn't know when. Now they're questioning whether the public option is going to be an option at all. Click here to follow the odds on Intrade.