Anyone who has done the "friends and family" financing thing will appreciate a service called LoanBack.  It’s basically a site that lets you set up a loan, either as the lender or the lendee, and then generates a custom promissory note with whatever interest rate you agree to.  You can even set it up so that multiple people can make loans to the same person, which is ideal for someone trying to get a small business off the ground.

This is one of those ideas that is simultaneously simple and brilliant.  Wish I’d thought of it.