TRECEVAL is a program to evaluate TREC results using the standard, NIST evaluation procedures.

Provides a framework along with several implementations that allow to perform Query Expansion (QE) with the use of Apache Lucene.

Nutch is open source web-search software. It builds on Lucene Java, adding web-specifics, such as a crawler, a link-graph database, parsers for HTML and other document formats, etc.