Essentially, you can lend the money so long as you don't comingle it with other money. It'd be a private loan between you and someone else. Recognize that it's risky--you might not get repaid. And therefore you should charge interest (and perhaps points) to adjust for the risk.
Example: Where I am, real estate investors sometimes use either hard money or private money. They're similar, but not the same. Usually, the loan is secured by a note on the property. If the loan is big enough, it's a first mortgage. More often, it's a second mortgage. And it's all negotiable, but private money might cost/earn 12% plus 3 points. The 12% is the annualized rate, though the term typically is 3-6 months. Hard money is somewhat more expensive--like 15% plus 5 points.
Check your state's usury laws. Those types of rates usually aren't close to the maximum permitted, but you want to be sure.
As for the questions from people on where to borrow--do an online search for "peer-to-peer lending." There are a couple of reputable companies out there. Basically, someone posts a need for a loan. They're scored as to credit worthiness, background, etc., and put into one of 5 or 6 categories, based on creditworthiness, along with a rate of return that investors can receive. Investors can buy small amounts of that loan. Example: Someone wants to borrow $5,000 for 3 years. The interest rate to the borrower could range from about 7% to 25%. Then investors commit to making part of that loan--anywhere from $25 to the entire amount. The investor receives about 1.5% less than the borrower is charged. Now, some of the loans go bad, and the companies attempt to collect. However, they're not always successful. But if you spread your investments out enough, statistically you should end up with a nice return. Example: I've been doing that for over a year with one of the peer-to-peer lenders. My annualized rate of return, even with some defaults, is about 14%. That's somewhat better than the 1% your bank will pay you.
Hope that helps.