A Ruby file parser/interpreter/preprocessor that comments lines of code based on conditions at the time the file is required. Very handy to implement debugging logs and code that has to be commented (not just dynamically switched off).
Java exception extractor. This utility will parse all files (either plain text or bzipped) and tries to search for various exceptions. It then tries to match exceptions against grouping rules (regexps). It is also able to group unrecognised exceptions.