(CNN) -- Dog goggles, crazy cars, giant burgers and pancakes-in-a-can are examples of off-the-wall ideas that business owners say they've turned into moneymakers--sometimes generating millions of dollars.

Here are some unusual businesses that clicked:

1. CitiKitty. It's hard to escape the smell of a cat's litter box when you live in a 500 square foot apartment.

Rebecca Rescate found that out soon after moving to New York with her husband and her husband's cat.

Rescate had read a few blogs about toilet training cats, and she was able to teach her husband's cat in a few weeks.

But she realized there was no product out there to facilitate the process. So she developed CitiKitty. The training kit comes with a specially designed seat that gradually recedes as the cat adapts to its new potty.

2. Reserve a spot in heaven. Worried about your eternal happiness? This web-based business, founded by Nathan Davis and Edgar Kim, promises to book your spot in heaven for about $13.

The package comes with a "heavenly issues certificate of reservation", a first-class ticket to the pearly gates, an identification card and a travel guide.

It even comes with a money-back guarantee. (Wink, wink.)

If heaven's not your bag, you can also reserve a spot in hell for the same price.

Photos from www.LemonAidCrutches.com

3. The Heart Attack Grill. Many fast-food restaurants seem to be on a health kick these days, promoting wholesome new menu items while downplaying their greasy hamburgers.

The Heart Attack Grill, an independent restaurant in Chandler, Arizona, is doing quite the opposite. It prides itself on its unhealthy food, which includes unlimited french fries and half-pound burgers cooked in lard.

And it plays up a hospital theme. Waitresses are dressed as nurses, cooks are dressed like surgeons, and customers have to put on hospital gowns.

4. DressLikeAPirate.com. Shayna Vest sold vintage items on eBay in the late '90s, "back when you could make good money doing that."

Noticing a pirate subculture, she ordered a couple of pirate-themed pieces from overseas to see how they would resell.

Within 3 weeks, she had sold 75 pirate shirts from her home in Portland, Oregon. The rest is history.

Vest now manages a Web-based business that sells pirate costumes and 18th-century clothing. There are also rum barrels, treasure chests and other props for sale.

5. LemonAid Crutches. A small plane crash took the lives of Laurie Johnson's husband and 2-year-old son in 2002. She suffered a badly broken leg.

"Still on crutches the year after the crash, I needed some cheering up," Johnson said. "My sister and I decided it was time to do something with my ugly crutches. We had them professionally painted and covered the pas with gorgeous designer fabrics, and--voila--they made me smile."

That inspired Johnson to take the lemons that life had given her and make LemonAid Crutches, putting a designer spin on the drab medical devices.

6. Doggles. Thanks to Doggles, the creation of Ken and Roni di Lullo, dogs don't have to squint in the sunlight anymore.

The protective eyewear also shields their eyes from foreign objects, wind and ultraviolet light.

Doggles are modeled after sports goggles.

They have flexible, snug-fitting frames as well as adjustable head and chin straps to keep them in place. They're designed to fit a dog's unique face structure.

7. Turtle Transit. James Riseborough, a commercial sculptor, combined his design expertise with his love of cars to create Turtle Transit.

The company in Lancaster, Massachussetts, modifies vehicles and turns them into eye-catching mobile advertisements.

Turtle Transit has created advertising vehicles for companies such as Nike, MasterCard, Dunkin' Donuts, Ben and Jerry's ice cream and monster.com.

8. Batter Blaster. Sean O'Connor has made millions of dollars with Batter Blaster, an organic pancake-and-waffle mix that comes in a pressurized can like whipped cream.

The product is in 13,000 stores in America, according to Fortune magazine. "We aren't feeling the recession like everyone else is," O'Connor told Fortune.

"We are one of the few truly innovative products to come out in the egg-and-dairy set," he said.

Photo from www.EternalReefs.com

9. Cremation memorial under the sea. Forget about scattering ashes into the sea.

Eternal Reefs, a company founded in Decatur, Georgia, by Don Brawley and George Frankel, helps families turn a loved one's ashes into an environmentally sound fish habitat.

In addition to helping marine life, the reefs help families heal, according to company president Chuck Kizina.

Family members can participate in building the reefs, he said, and they often bond as they become invested in the undersea world.

10. Lice'n Easy. Marsha Hill is a professional nitpicker.

That means she will come into your home and pick the nits, or eggs of lice, out of your children's hair.

The louse-removal service provides "immediate gratification, not only for me but for the families," said Hill, who is based in Huntington Beach, California.

She said the average family spends about 3 to 6 months trying to completely get rid of head lice.

11. Advanced Bio Treatment. After police collect evidence at a crime scene, Jerry Turner's business will come in and clean up whatever's left behind: blood, urine, feces, hazardous materials, you name it.

Turner owned an insurance company a few years ago when he read a magazine article about a crime-scene cleanup business.

"I realized I could do very well in the industry," he said. He left the insurance industry behind and never looked back.

12. Rescue Critters. Rescue Critters are lifelike animal mannikins that help train veterinarians and rescue workers.

The company was founded by Craig Jones in Van Nuys, California.

Jones' newest training mannikins represent 6-month-old puppies, and they can be "operated on" by people learning to spay and neuter dogs. (CNN)