Technologist Jim Paris has created a simple terminal emulator for Python which is quite useful - it allows connection to two or more device in the single window. Setup is via the command line, and each device connected can be colour-coded to save confusion. What this has to do with Arduino is quite simple - when you're prototyping with more than one board at the same time - you no longer have the confusion about which window is for which board.
Kudos for Jim for creating this tool. For more information visit here and the download files are here. And for more, we're on twitter and Google+, so follow us for news and product updates as well.
If you're looking to work with multiple Arduino Leonardo-compatible boards at the same time (or even one!) - look no further than the Freetronics LeoStick. Apart from being one of the smallest Arduino-compatibles on the market with USB, it also has an onboard RGB LED and piezo for sound and knock detection:
