LabKithra: People like you liked these

Kithra is a recommendation engine built on item-item collaborative filtering, the approach Amazon scaled to production. The signature technique computes cosine or Pearson similarity over a ratings matrix and then makes a k-nearest, similarity-weighted prediction - no training, just similarity and a weighted mean - tested with the full "fan of Inception leads to Interstellar" scenario and an honest cold-start case. It is a from-scratch, dependency-light build you can download and run locally.