Tiling window manager for OS X similar to xmonad.
Amethyst for Mac allows you to resize and reposition windows in real time. It runs exclusively on the new OS X Mavericks, for which it is highly optimized. A useful app, it has a rather steep learning curve, which makes it challenging to use even for seasoned Mac users.
Snap windows into position by dragging them to the edges and corners of your screen.
Move and resize windows with the keyboard.
Allows you to effortlessly resize windows to exactly half your desktop.