Your computer could be helping to save lives when you are not using it to play games or surf the internet.
Instead of it sitting idle, it could be taking part in scientific experiments being distributed across thousands of computers on the internet.
Drugs to beat cancer and flu are starting to be tested in simulations split up and run on personal computers that would otherwise be doing nothing useful.
Some of the companies behind the projects are even planning to pay to use idle computers.
Seti search
The idea follows the huge success of the Seti@home project which uses idle computers to search for signs of extraterrestrial life in radio frequency data gathered by the Arecibo telescope.
When the PC is on, but not being used, a screensaver starts up that analyses data from the Puerto Rico observatory.
Over two million people have downloaded the Seti@home screensaver clocking up over 350,000 years of computer time. Far more, and far cheaper, than Seti could manage by itself.
Now, companies such as Entropia, Parabon, Distributed Science and Popular Power are planning to use the same idea to do terrestrial scientific research.
If the companies can sign up enough people, computational projects that would otherwise take months could be completed in days.
Computers against cancer
Virginia-based Parabon is collaborating with the US National Cancer Institutes molecular pharmacology lab on a project to simulate how cancer cells react to different drugs.
"It allows individuals to directly contribute to cancer research and may lead to important discoveries," said Steven Armentrout, chief executive of Parabon.
Next Parabon is planning to study ways of reducing the side-effects of chemotherapy.
Participants in the Popular Power project will be tackling influenza.
Its screensaver looks at how different drugs fare when combatting mutant strains of the influenza virus. Popular Power is planning to pay participants but has yet to say how much.
Delaware-based Distributed Science, via its Process Tree network, is planning to run computational projects that will pay participants to use their machines.
Waste cycles
Potential customers include film studios creating computer generated films. The detailed images seen in films such as Toy Story and Antz take a long time to generate.
Some of the most action-packed frames from Toy Story took a network of over 100 computers 20 hours to generate.
But letting your computer work while you are idle will not mean you can stop working. Distributed Science says payments will probably only be enough to cover monthly internet provider subscription fees.
Already 100,000 people have joined the Process Tree network.
"Our network has a processing power three times the capacity of Asci White, the world's most powerful supercomputer," said Jim Albea the founder of Distributed Science.
IBM's Asci White will use over 8,000 processors and be capable of performing 12 trillion calculations per second.
Currently, the Distributed Science network is doing the number crunching on a study of the best way to store nuclear waste. The screensaver simulation models how gamma radiation leaks from storage containers made from different materials.
The networks set up by Popular Power, Parabon and Distributed Science Entropia will act like huge dispersed computers.
Unlike Seti@home, participants will not simply download data, analyse it and send it back.
Instead, significant results, such as a weakness in a flu virus project, will be passed among participants. The companies hope this will speed up the whole research effort.