Often start-up companies will come up with an idea that hits it big but not where they were going at all.  My favorite example is that 3M was trying to find a super-strong adhesive when they accidentally discovered a super weak one.  No one knew what to do with the stuff so it sat on a shelf for years before a scientist at 3M was singing in the church choir and wanted a way to keep the bookmarks for songs in place.  Post-it notes was born; arguably one of the most successful products in 3M history.

More recently a researcher was looking into ways to stimulate the brain portions that says “I’m full” to treat obesity.  He discovered instead a method to trigger memory that may be a new treatment for Alzheimer’s.