Have an elegant solution to an issue and want to save others the pain? Create a subpage under this page and write away. Use Cases filled with marketing jargon will be removed. This is not a place to tout why your product is the greatest thing since sliced bread. It is a place to share real solutions to real problems.
Using SpanQuery for database join
Using deletion neighborhoods for fast Fuzzy queries (http://wiki.apache.org/lucene-java/FastSSFuzzy)
Using Brics for fast Regex queries (http://wiki.apache.org/lucene-java/FastRegexp)