active record validation failure upon joining game

gistfile1.txt

vagrant@vagrantup:/vagrant$ bundle exec rspec spec/integration/boards/show_spec.rb 
..F..

Failures:
  1) Showing Boards should start the countdown to match the server timer
     Failure/Error: @user.join_game!(@game)
     Validation failed: User has already been taken
     # ./app/models/user.rb:30:in `join_game!'
     # ./spec/integration/boards/show_spec.rb:59

============================================

  def join_game!(game)
    self.game_board = game.game_boards.first
    ugb = user_game_boards.create(:game_board => self.game_board)
    ugb.started_at_epoch = ((ugb.created_at.to_f) * 1000.0).to_i
    ugb.save!
    self.save!
  end

============================================
  before :each do
    @user = login_as_user
    @game = Factory.create(:game)
    @game.generate_boards
    @board = @game.boards.first
    visit_first_board(@game)
    sleep 1
    all_board_rows.should_not be_empty
  end