A rackbar is a person who is making a fool of themselves or is just naturally an idiot or moron.
"'Doz, you're such a rackbar you fucking faggot."
Term used by the homeless Philedelphian Willey James Huff in conjuction with rackem rack. The meaning is unknown but is still hilarious and can be seen in a collection of videos on YouTube.com.
Racke' rack, rackem' rack, RACKBAR!