Hackathons are about gathering groups of like-minded people together and giving them a limited amount of time to either solve problems or find better ways of doing things with the use of technology. There are a number of hackathons hosted by larger companies that are open to external participants but there's no reason why your company can't host its own event that may end up being more beneficial.
A hackathon is more than just about throwing people together to quickly come up with ideas for problems; these events have the potential to unearth new opportunities for organisations in terms of revenue, business models and improving employee satisfaction. It's worth hosting an internal hackathon because employees can focus on finding new solutions for issues that are specific to their business, unlike external events which usually has the broad objective of simply stimulating new ideas.
According to Gartner research director Mark O'Neill, the first step towards hosting a great hackathon is to align it to the strategic objectives of senior business executives; but this is a delicate balancing act:
"If the purpose is too explicit and structured, it may diminish innovation, while at the other extreme, hackathons that are overly social may fail to deliver because the event has no shape or form. A challenge-based hackathon will help to avoid low-quality and unfocused ideas."
There are plenty of other elements to consider when it comes to a hackathon, including the location of the event, how to market it within your organisation and post-hackathon actions. O'Neill has more advice on hosting a successful hackathon internally, which you can find over at Smarter With Gartner.