Android and iOS App Olympics held in London in video

Nikita has been coding for two days straight, and it's starting to show. It's Sunday afternoon at the Mobile App Olympics, held just above the Smithfield chicken market in East London. Around 100 coders, designers and wannabe entrepreneurs are hunched over their laptops.

They've been working since Friday evening on the iOS or Android app that could help them hit the big time. Sustained by sandwiches, crisps and gallons of Coca-Cola, Nikita's team is working on an app called Vouback, a way of making it easier for businesses to harvest customer feedback using Android phones.

He only met his teammates for the first time on Friday evening, but they've already produced a design, a working app, a website and -- of course -- a Facebook and Twitter presence. If they win the London heat, they'll go on to compete against the best developer teams from Paris, Berlin, New York, San Francisco and Dallas in a bid to win Mobile App Olympic gold.

Crunching code for 48 hours may seem like an odd way to spend your weekend -- especially if, like Nikita, you have a day job as a software developer -- but it's becoming a popular activity. Hackathons like the Mobile App Olympics now take place in cities all over the world almost every week, and they've resulted in a wave of innovation in the app business.

With new, easy to use programming tools springing up all the time, the development time and cost of a mobile app has spiralled to almost zero. You don't need a million-euro marketing budget and a stand at Mobile World Congress -- anyone with a good idea and the ability to mash together a couple of lines of code can enter the app business.

"People really don't have much of an opportunity cost when they come to one of these things," explains Olga Pavlovsky from TechMeetups.com. "You can go clubbing over a weekend then spend a day in bed afterwards. Or you can come here, meet some really great people, and create a really interesting project."

I went to the Mobile App Olympics to investigate the rise of the hackathon in this video. Who will win the app gold medal? Hit play to find out. For more information and to vote for the best international app, check out the App Olympics website -- voting closes tonight.