Leapdroid is an Android emulator, a piece of software that allows you to run Android apps on other devices. Touch gestures are mapped to keys on the keyboard: for instance, swiping left becomes pressing the left arrow key. Emulation allows you to use your favorite apps without having to worry about clunky touchpad typing, battery life or processing power, while a computer's larger display makes text and images easier to see.
A boon for mobile gamers
Leapdroid targets its advertising at the mobile gaming market, and some of its features are clearly intended for this purpose. For instance, you can create multiple emulator profiles simultaneously, allowing you to play the same game while logged in from two different accounts. Tools like this have limited use unless you play a lot of action-limited mobile games. Installation and use are simple. Keymapping can take a while for complex apps, but in most cases the translation simply means clicking instead of tapping, especially for games.
A reliable Android emulator
If you want to run Android apps on your PC, Leapdroid is a solid tool for the job; there are a few tricky things about the transition to get used to, but they mainly come from trying to approach Android apps with a different set of tools. Support covers most apps, with only rare exceptions.