What is the attraction third-party candidates?

For me: two major parties don't meet my beliefs.  Also don't like how misconstrued they seem to be from the rest of the population.  I voted libertarian because the last presidential candidate, Bob Barr, 

The libertarian party is the biggest third party in the United States.  Ron Paul, currently running for the Republican nomination, was closely affiliated with the Libertarian party.

I knew that registering as a libertarian would eliminate me from participating in the Republican and Democratic primaries but it did not bother me.  The way I figured, I rather add to the libertarian parties numbers than try to align myself than fit with a major party that fit "well enough."

One of the characteristics I admire about third party candidates--and other candidates that aren't necessarily the party's frontrunners--is their perseverance.  They don't give up, no matter how badly they get beat in the election.  And they always try to reach a minority, something that the major political parties have neglected to do.