We invite you to become one of the first participants in an exciting global experiment of modelling and prediction world’s climate in the coming century – the largest experiment of its kind ever undertaken! And to make the invitation real, yesterday saw our brand new web and application server coming online with a fully-qualified domain name of climateprediction.net. This happened just in time when the project enters its Beta testing phase of the climate model software, which would be supplied to the participants. The aim of climateprediction.net project is to harness the idle capacity of worldwide computers at home and at work by running a state-of-the-art simulation of climate courtesy of UK MetOffice. Each participant will have their own ‘personalised’ model accounting for slight alterations of various climatic phenomena. Altogether, the project team consisting of Oxford University, Open University, RAL and other associates hopes to attract a user base of hundreds of thousand users. This enormous population will assure a statistical robustness and validity of the climate predictions. In addition to running a software model, the participants would be able to take advantage of a knowledge-intensive content on the project website, which is currently under construction by the teams at KMi, Earth Sciences (both from The Open University) and Oxford university. The project team is delighted to invite you to its new web site, and we would like to take this opportunity to invite you to participate in the Beta testing of the climate models. If you want to become a potential Beta tester, please visit the information page at URL climateprediction.net/info/download.php, and follow the appropriate link to express your interest. Should you decide to lend your home or work PC for testing, you would be required to download and install a model and leave it running for a few weeks – no advertising banners popping up, just sitting quietly in the background and crunching the numbers.