Eiten is an open source toolkit for building portfolios using statistical and algorithmic strategies. It implements methods such as Eigen Portfolios, Minimum Variance Portfolios, Maximum Sharpe Ratio Portfolios, and Genetic Algorithms to optimize stock portfolio allocation. The toolkit includes a backtesting framework for testing strategies against historical data and uses Monte Carlo simulation for forward testing. It integrates with Yahoo Finance for data retrieval and relies on scikit-learn and scipy for the underlying mathematical computations.