Windows by default has power configuration set to make your computer sleep so it can save power but many a times you don’t want your machine to go to sleep and reasons can be many. Either you are downloading or compiling some code or burning music and went for a coffee but when you come back, your computer went to sleep and all your work is wasted.
For these temporary situations, David Anson @ MSDN Blog has created a nifty utility which he calls as insomnia. This utility once launched makes sure your computer does not go to sleep even if your power configuration is set to.
In the background it make Windows believe that you are using the computer and hence the computer never goes to sleep. However you monitor can turn off as it does not come under sleep conditions.