white_elephant.rb

recipients = ['james', 'stephanie', 'lauren', 'james k', 'brittany', 'lyrica', 'dad', 'mom']
senders = recipients.dup

results = recipients.map do |recipient| 
  sender = senders.sample
  while(sender == recipient)
    sender = senders.sample
  end
  senders.delete(sender)
  [recipient, sender] 
end

results.each { |result| puts result[0] => result[1] }

Result:

{"james"=>"dad"}
{"stephanie"=>"lauren"}
{"lauren"=>"brittany"}
{"james k"=>"mom"}
{"brittany"=>"james"}
{"lyrica"=>"stephanie"}
{"dad"=>"james k"}
{"mom"=>"lyrica"}