Automatically Take Screenshots with Auto Screen Capture
Auto Screen Capture is a free and open source Screenshot taking application for Windows. Using this application you can take screenshots at a chosen interval while you work and play games on your computer. In this application you can select the screen capture options from the system tray icon. From here you can select capture region and save it on your clipboard, auto Save or open in editor for edit. It supports automated screen capture sessions.
It also comes with build-in automated screen capture sessions calendar to help you keep track the screenshots taken. It is released under GNU General Public License (GPLv3).