How do I use AirDrop from the Terminal? Is there a way to share a file over AirDrop via Terminal on Mountain Lion? How so?
I have not (yet) figured out a way to send files via Airdrop using the Terminal, but you can set your computer to receive files via Airdrop using the following shell script:

#!/usr/bin/osascript
tell application "Finder"
    activate
    tell application "System Events" to keystroke "R" using {command down, shift down}
end tell