To turn left. Used with Ralph and Dave; Left; Right; and Straight ahead. Named for David Ralph Lewis who in the mid 60's in Duluth Minnesota stole many cars for joyriding and to see how many times he could roll the cars. A pure manic who died of cancer at 27 years. Since then "Hang a Ralph", "Hang a Lewy" or "do a David" have entered the popular lexicon.