I love the underdog, especially in politics. I voted for Nader when I lived in Texas, and I can remember watching the Ross Perot infomercials when I was in high school. It takes a unique personality to spend time and money arguing and fighting against a political process that is impossibly larger and immovable. They remind me of Sisyphus, except they volunteered to roll the boulder up and down the hill. All of them are idealists, some are dreamers, some extremists. All have a lot of chutzpah.
There are a bunch of candidates that have gotten little to no attention. Here are my favorite of the bottom tier. There are probably two dozen others I found that seemed to be very similar in their devotion to low taxes, repealing health care reform, and hawkish foreign policy.
Buddy Roemer - Definitely my favorite. I think I would actually vote for him if he was the Republican candidate. He is trying to fund his campaign only with small donors, which I admire. He used to be a Democrat, then switched to the Republican party. He has federal, state, and business experience. Unfortunately, I think he is going to drop out.
Jon Huntsman, Jr. - The more liberal version of Romney. He has foreign service experience and seems likeable enough.
Almost no one runs against a sitting president of your own party.
Darcy Richardson - even more liberal Democrat. Bring on single payer health insurance!
Randall Terry - extreme pro-life Democrat. Is this guy in the right party?
Rocky Anderson - He was mayor in Salt Lake City and now founder of his own political party. Why does he think that will translate to the US presidency? I do not know.
Vern Wuenshe - He reminds me of a high school economics teacher. No charisma.
John Davis - the flag painted wrench in his photo is hilarious enough. Tea Party-esque politics
Mike Ballantine - living in Vietnam. He is running his campaign from there. Enough said.
Stewart Alexander and Alex Mendoza Socialists. Really. There are Socialists for president!
Scott Keller - Occupy the Whitehouse? He owns the website in case you were thinking of squatting there.
Peta Lindsay - She is a 27 year old anti-war activist. She missed class on the day they explained you needed to be 35 to run. Maybe in 8 years she will run again.
Mosheh Thezion - Doesn't believe in smiling for photos. Doesn't like having his picture taken. Doesn't proof-read his website for his campaign. Quotes a lot of scriptures.
Deonia Neveu - She doesn't believe in being "personally worshipped and glorified", like the other guys? She says she has a lot of drive though.
Jack Fellure - Runs every time. Last name rhymes with failure. The Bible is his platform.
Andy Martin - The guy that started the Birther idiocy. Now is trying to argue for Obama really being the son of liberal activist Frank Davis.
Jeff Siggans - President and Pope. He is running for both. Really.
Jonathon Sharkey - This guy should be on a sex-offender's watch list. He drinks blood, has a bad mustache, and has unhealthy relationships with teenage girls.
And there are more! Wikipedia has a whole list of alternative parties and their candidates here, including Roseanne Barr and the Naked Cowboy.