Wacky investment ideas that will make you go, 'Hmmm ...'

People sure can come up with some strange investment ideas.

"Every time I think I've heard it all, I realize that people are much crazier than what Hollywood can think up," said Kevin Meehan, certified financial planner and regional president of the Wealth Enhancement Group.

"One of my clients and his friends had a vision: If they opened a gentleman's/strip club near some major sports facilities, they thought the demographics of those who attended could match up," he said. "When spending pre- and post-game activities, they would offer some unique options."

Meehan's response?

"After I finished laughing out loud ... well, the rest of the response is unprintable," he said. "I didn't judge it. I don't know much about this industry. I don't imagine there was a prospectus available. I suppose you need some common business skills, like hiring and marketing."

"I had a client a few years ago who wanted to invest in a publicly traded firm that made marijuana processing equipment," said James Kinney, CFP and founder of Financial Pathway Advisors.

"He was insisting that the drug would soon be legal in many states and this would be the next big thing," he said. "I dismissed the idea at the time, but maybe I should have listened."

Kinney gave the client the polite brush-off, saying, "OK, I'll consider that."

"In the meantime, I was thinking, I wonder how that fits into your asset allocation," he said. "It doesn't get into any of the socially responsible funds."

Maybe sourcing drugs is a better idea?

When Holly Thomas was a banker in the early 2000s, a real estate developer client approached her about a commercial loan to invest in a poppy farm in Colombia. She is now a CFP and founder of her own firm, Holly P. Thomas.

The client, originally from that South American country, had a good reputation for repaying his loans. Not wanting to make any accusations, Thomas decided to play it straight and ask him some questions.

"What kind of rate of return do you expect?" she asked. About 15 percent to 20 percent, he replied.

Read MoreInvestors puzzle over alternatives

Thomas said she thought, OK, and then came up with an objection: "How do you know you'll get this return?" she asked the client.

He replied that he already had the buyers lined up. "That's when I got scared," Thomas said.

"In retrospect, I didn't know whether to call the FBI, but he had such a straight face and made me wonder: Could it have been about poppy seeds?"

The loan was declined.

"The craziest request was bitcoins," said Michael Miller, CFP and wealth manager with Miller Premier Investment Planning.

An elderly client of Miller's got the idea from an email newsletter, researched the past returns and decided to check with his advisor.

Miller said he thought, Oh, no, not another one.

"Did he understand what a bitcoin was? Yes," he said. "Did he understand the mechanics behind it? No."

Read MoreGoing alternative for the wrong reasons

Miller told the client: "I believe this is another fad. Not a place for a retiree."

"I had this picture in my mind of a guy going with a barrel of cash and exchanging it for bitcoins," he said. "But if bitcoins are supposed to be better than dollars, why are they taking dollars for them?"

How about some Iraqi dinars?

"It defies rationality," said Rick Kahler, CFP and owner of Kahler Financial Group, referring to an inquiry from a client in his 50s who was thinking about how to fund his retirement.

"He wanted to buy 1 million Iraqi dinars for about $2,000, thinking that when Iraq emerges from war and stabilizes, they'd be worth $1 million," Kahler said. "I thought, Oh, my gosh. Where do I begin?"

He added, "It takes a while to get your head around the question, and it would take hours and a whiteboard to explain, so I just said, 'I don't think it's a good investment at all,' " he said.

"A few years ago, there was an offering of Green Bay Packers stock, which isn't wacky but actually pretty cool," said Donald Nicholson Jr., CFP and senior financial advisor with Donald W. Nicholson & Associates.

"A client called to ask if this would be a good investment," he said. "I laughed and said, 'If they won!' "

"I agreed it would be cool, a good stock to hold on to," Nicholson added. "It's a guy thing, with bragging rights for your buddies."

He recalled another "different" idea. Nicholson had a young client who wanted to buy truckloads of scrap metal "down south" and sell it "up north."

Read MoreDrunk on liquid alternatives?

"Our response was, 'Are you kidding me? That's a terrible investment. This makes no sense,' " he recalled.

Nicholson said he suspects the client eventually tired of being told no.

"We never heard from him again after that," he said. "Maybe our portfolios seemed too boring to him."