Apache Lucene - High-performance, full-featured text search engine library written entirely in Java.
ReadingIQ - ReadingIQ is the most leading digital learning library app for kids ages 2 to 13.
Six Degrees of Wikipedia - Find the shortest path between two subjects
EduKittyABC - ABC Games for Kids – EduKittyABC is a fun tracing English alphabet educational app developed and published by Cubic Frog Apps.
Sphinx Search - Sphinx is an open source full text search server, designed with performance, relevance (search quality), and integration simplicity in mind. Sphinx lets you either batch index and search data stored in files, an SQL database, NoSQL storage.
Bini Super ABC - Bini Super ABC! Alphabet Games for Toddlers and Kids is a fun education app for those kids who want to learn letters and sounds of the whole alphabets.