LED Blink

http://elinux.org/BeagleBoardOpenOCD#LED_blink_example

Beagle Board has a series of LED lights. Those can be tested using the LED blink test program, which can be found on the link posted above.
It might be possible to create your own LED flashing pattern.
LED flashing pattern can also be used as a status indicator. One way is that it can be used to indicate whether a particular event has occurred such as boot completion. It can also be used to indicate status of a particular resource such as network connection, bluetooth connection, error detection.

One usage I can think of for this LED blink program is that, it enables an user to use a beagle board outdoors without having to use a laptop or a monitor to see whether a particular program is ready or not.

On the IRC channel, # beagle, IRC nicks GrizzlyAdams, Nader, were discussing about it. The thread can be found at http://www.beagleboard.org/irclogs/index.php?date=2009-11-19#T06:01:50

Evtest

http://wiki.davincidsp.com/index.php/Evtest
The above link has code and instructions for conducting an Evtest.
Evtest is an open source tool, that can be used to test several different HID drivers and devices such as mouse, keyboard, joystick, touchpad.
Evtest can enable a user to test a particular HID device on beagle board.

It enables an user to test a particular HID device thoroughly such as testing all the keys of a USB keyboard or testing all the axes of a USB mouse.

Instructions regarding how to execute and use Ev test are on this link:
http://wiki.davincidsp.com/index.php/Evtest

In the IRC channel # beagle, IRC nicks super, and prpplague were discussing about it.
The discussion thread can be found at:
http://www.beagleboard.org/irclogs/index.php?date=2009-11-13#T20:11:34