check_mysql runs as a daemon with a continuous connection to MySQL, watching the list of running SELECT queries. It enforces a timeout for queries: if a query runs too long, it is killed and a report including the query and EXPLAIN output are emailed. Its probably not something you'd want to use on a production system, but it is very useful during development and testing phases for finding, analyzing, and optimizing SQL queries.
EMS is an event manager for PIKT and other monitoring tools that allows you to send UDP events instead of mail messages from PIKT alarms (not alerts). Those events are sent as XML ciphered (you can use your favorite cipher) messages via UDP, from the client (epush) to the manager (eventd), consolidate events together (grouping events together or discarding them when necessary), and store events in a backend database. The database is your choice, although EMS has been developed with MySQL in mind. Hooks are in place to provide future advanced event correlation, "management" of events via a web interface, display alerts on user uploaded maps, and send data from your performance monitoring application to RRDTool via special 'data' events.