If you want to raise money for something these days, the answer often is: Ask the public for it.

Crowdfunding sites such as Kickstarter, Indiegogo and GoFundMe have become the go-to resource for projects as diverse as starting a business, turning an invention into reality or funding a personal goal or need.Talked-about tech—including the Pebble smartwatch and the vibrating HAPIfork—got a start on crowdfunding sites, and after the Boston Marathon bombings, friends and family of victims used such sites to raise money to help with medical bills.

Globally, more than a million successfully funded campaigns raised $2.7 billion in 2012, up 81 percent from the previous year, according to research firm Massolution. This year, it expects projects could clear $5 billion.

While there are plenty of projects that fall into the mainstream, others are more … unusual. Think potty parity, pizza and a salt-loaded rifle for pest control.

In fact, that's part of the crowdfunding appeal. Sites are a cheap way to gauge the market for a business or gadget, said Jack Vonder Heide, president of Technology Briefing Centers. "If people think it's a stupid idea, they're going to tell you very quickly," he said. Or campaigners might discover they've tapped into a surprise hit.

GoFundMe, Indiegogo and Kickstarter reported that these seven projects are among the more unique they've come across:

By Kelli B. Grant, CNBC.com
Posted 19 June 2013

Goal: $30,000

Raised: $26,201

Lines for the ladies room often seem longer—particularly when restrooms are in short supply. That's been the case for years at the James J. Musso Boys & Girls Club in Lakeland, Fla., said director of development Kelly Lane. Because the facility was originally a boys club, male toilets outnumbered female ones by 3 to 1, requiring the female campers to use portable toilets for the past two summers. Lane said the club, like many nonprofits, was operating on a slim budget. "We needed the funds, but we needed it to have a built-in audience," she said. Their GoFundMe campaign, in conjunction with local fund-raising efforts, generated enough to build new restrooms, which opened in early June.

Goal: $15,000

Raised: $16,587

"There's a museum out there dedicated to french fries, kiwis, chocolate, Pez dispensers,even burnt food—and yet, no one has ever thought to curate a museum honoring what is arguably the most celebrated food on the planet," wrote the would-be museum founders in early 2012, when their Kickstarter goal launched. A year earlier, Guinness World Records had dubbed the pizza memorabilia collection the largest in the world. Of the 326 backers, 285 gave enough to enjoy some free pizza—claimable since the restaurant-museum opened in September 2012.

Goal: $15,000

Raised: $577,636

A pinch of table salt in this miniature shotgun packs enough power to kill flies and other insects within a 3-foot range. Creator Lorenzo Maggiore was hoping to raise enough to produce at least one small run of the Bug-A-Salt; by the time the Indiegogo campaign ended, buyers had bought more than 21,000. "It was very strange, surreal," said Maggiore. Bug-A-Salt was a one-man operation at the time, so Maggiore hired a team to help him meet the demand. The device started shipping a month later, and is now on sale at BugaSalt.com.

Goal: $10,000

Raised: $10,530

Years after author Ken Kesey's road trip on the psychedelic Furthur Bus (immortalized in Tom Wolfe's "The Electric Kool-Aid Acid Test"), Kesey parked the bus in a swamp on his property in Oregon. His son and daughter-in-law, Zane and Stephanie Kesey, reunited with some of Kesey's Merry Pranksters in 2005 to haul the bus out, said Jason Johnson, director of the nonprofit Furthur Down the Road Foundation. The first round of fundraising on GoFundMe helped set up the foundation, but it's just the start. "Our goal is to raise $1 million by the end of 2014," he said. "We will be restoring it with the help of a great number of artists and restoration experts."

Goal: $7,500

Raised: $8,982

If an acorn falls in the forest, how many squirrels will fight over it? Unpaid researchers and volunteers conducted a census of squirrels in the Inman Park neighborhood of Atlanta in early 2012. Their Kickstarter goal came in after the fact, to print a run of posters of infographics using its data—detailing counts, clusters and individual squirrel details—and to fund future censuses. More than 100 backers bought in, 68 of them contributing enough for a free poster. "Everybody has a squirrel story, because we interact with them on a daily basis," said organizer Jamie Allen. "We knew we had an audience for this sort of thing."

Goal: $10,000

Raised: $11,476

No city is complete without its own font, said the creators of this Kickstarter project, which set out in 2012 to create a unique typeface for Chattanooga, Tenn.—the first such custom typeface for a municipality. Now Chatype can be spotted on the city's website and library signage, among other places. The font is also available as a free download for users who watch a three-minute video.

Goal: $5,500

Raised: $2,050

Within 24 hours of turning 17 in July, Robert Pinksten is hoping to take the tests to become licensed as both a helicopter and airplane pilot. Doing so would set an aviation record. "I'm the only person in the United States who has even tried, to my knowledge," he said. In early June, Pinksten was still less than half-way to his goal on GoFundMe; he plans to take out a loan for the balance if necessary.