Android ICS (4.0 and up) how to take screenshots straight from adb

Taking screenshots of the application you're developing has never been easier since Android 4.0.
If you have your device in debugging mode, just list the devices to see if the tablet/phone is visible:

adb devices

and then take screenshots in the following manner:

adb shell /system/bin/screencap -p /sdcard/screenshot_1.png