NOTATIONAL VELOCITY is an application that stores and retrieves notes.
SizeUp allows you to quickly position a window to fill exactly half the screen (splitscreen), a quarter of the screen (quadrant), full screen, or centered via the menu bar or configurable system-wide shortcuts (hotkeys). Similar to "tiled windows" functionality available on other operating systems.
This free tool fixes an inconvenient behavior of green Zoom button in Mac OS X. It will always expand windows on a full screen instead of strange resizing.
WaterRoof is an IPFW firewall frontend for Mac OS X with a easy interface and many options.