Via Students for Liberty on Facebook, I saw this Politico article reporting polling data showing "Record demand for third party." As one of the comments points out, it's the sort of thing that gets attention periodically but that never really goes anywhere (in my limited experience with alternative politics).
I know this from experience. I was an enthusiastic supporter of Harry Browne's Libertarian presidential campaign in 2000 and for Libertarian candidacies around Alabama, and I remember being mystified at the number of people who held their noses and voted for Al Gore or George W. Bush in the Presidential election even though they were more closely aligned with Browne, Ralph Nader, or Pat Buchanan. I witnessed the same phenomena in 2008 and 2012 in Tennessee and Alabama. I might have had a bit more sympathy if these had been swing states, but there was absolutely no way Obama was going to win either. I've written on the (il)logic of collective action in Presidential elections a few times for Lifehack, the Beacon, and Forbes.com.
I'm therefore skeptical that a third party will make much headway in the next few election cycles. Thus, I propose a bet: my $100 against your $20 says that no third-party challenger will win a seat in the US House of Representatives or the US Senate in 2014. Note that I would still win if someone wins as an independent: someone might win as an independent, but I don't expect anyone running under the Libertarian or Green or Socialist or whatever banner to win. It's a bet I would be very happy to lose, but I certainly don't expect to. Email me if you want in on the action or if you want to propose an alternative.