Remove duplicate elements

Given a Array, create a derived Array containing only the unique elements

Remove duplicate elements
You are encouraged to solve this task according to the task description, using any language you may know.

Ruby

 ary = [1,1,2,1,'redundant',[1,2,3],[1,2,3],'redundant']
 uniq_ary = ary.uniq
 # => [1, 2, "redundant", [1, 2, 3]]