Control your device remotely via SMS by sending shell commands.
An endless amount of possibilities that you can do with this app.

Some few examples of a lot more......

-Listing of folder contents
Example:
ls /system/bin

-Finding out how much diskspace is used
Example:
df

-Showing environment variables
Example:
printenv

-Listing installed packages
Example:
pm list packages

...but best of all...you can even start and control other programs(activities) with the activity command line manager(am)

Examples:

Play a video with YouTube

am start -n com.google.android.youtube/.PlayerActivity -d http://www.youtube.com/watch?v=MTT-crZBB0k

Play a song from sdcard with media player

am start -a android.intent.action.VIEW -d file:///sdcard/YOURMP3SONG -t audio/mp3

A lot to explore on your device!!!

More information on intents:
http://www.openintents.org