iTerm2 is a replacement for the Terminal application that comes with OS X. iTerm2 has some great features like auto updates, unlimited history, mouseless copy, instant replay and tabs but far and above the best feature is the ability to split panes! Split panes allows you to divide your single iTerm2 terminal window both vertically and horizontally.
You could split your terminal into a veritable Fibonacci spiral – it is that awesome!
To split your terminal vertically: Command + shift + D
To split your terminal horizontally: Command + D
This allows you to cram all your active sessions onto the same screen, making good use of that giant glossy real estate! Enjoy! #nerdlife
Screenshot of iTerm2 in the classic Fibonacci spiral configuration.