By now you have probably seen the multiwindow feature in devices like the Galaxy S4 and the Galaxy Note 2. The feature allows you to use multiple screens at once on your display. This is great for productivity and also for the Awesome factor! Native Multiwindow does have its limitations. Only some apps are included. These are normally stock apps and tw apps. There is an app that will allow you to modify your multiwindow and add any app you like. You can even enable every app in your app drawer for use with multiwindow. Some roms do this natively like BeansTown106's Jelly Bean's Build, and Sbreen94's Hyperdrive rom, but if you aren't in to running Roms on your device this app will do the trick.
Play Store - Free
Play Store - Pro