Web wizards will have a field day with government data, writes Nick Galvin.

Nearly 150 web experts and developers will descend on Canberra this weekend for a mass ''geek sleepover'', building applications and mash-ups through the night using government data.

The Federal Government is underwriting the event, called GovHack, which organisers claim is a global first.

''As far as we can tell, this is the first one anywhere in the world that a government of any size has said: 'Come and do cool stuff with our data,''' says GovHack producer John Allsopp. ''We provide power, Wi-Fi, food and caffeine and people hack away for 24 hours. At the end there is a show-and-tell.''

There will be a massive range of information on offer at the geek-fest, ranging from research on the distribution of frogs around South Australia to detailed crime statistics. The full list can be viewed at data.australia.gov.au.

Quite what the developers will come up with from this pile of data is anybody's guess - but that, Allsopp says, is the beauty of the event.

''What I often say to people, whether in government or private industry, is: 'Look, you can't imagine all the things we are going to do with your data. Let other people imagine that for you - let them fail and let them succeed.'''

The ''hack day'' concept was first started by Yahoo about 10 years ago and has since been taken up by a wide range of organisations keen to see what innovative uses can be found for their data.

And GovHack is part of a trend gathering pace around the world for governments to open up their data in formats that are easy for developers to work with.

''They are not only receiving and using your data and services, they are actually contributing to them,'' Allsopp says.

In June, the Government launched its Government 2.0 Taskforce, charged with making official data more accessible and usable. Taskforce chairman Nicholas Gruen is enthusiastic about the benefits. ''For quite modest expenditure you can create an asset which has this untold upside,'' he says. ''People can use it, they can play with it - either seriously or foolishly - and all sorts of fantastically good things can come out of it, as we have seen around the world.''

Some examples out of the US include a tool that maps the location of crimes within many large US cities using police reports (EveryBlock), an application that allows citizens to track the voting patterns of their politicians (Filibusted) and a site (SpinDifferent) that compares what the White House, the UN and Downing Street say on a given topic.

Closer to home, the Department of Health and Ageing has handed over data from its national map of public toilets to web developers, who recently launched a free iPhone app that identifies nearby loos.

Matthew Cashmore has been involved with hack days almost since the beginning and is now in charge of opening up data to developers from travel publisher Lonely Planet, which will stage its own hack day in Melbourne on November 7 and 8.

Cashmore admits it is easier to make the case for releasing data when dealing with governments.

''With government it's actually pretty straightforward because the argument is simply that the data is or should be available anyway - it's just that it happens to be available only in folders in the back of the public library,'' he says. ''All you are arguing is that it should be available in a more acceptable form.''