pasvnag_lite is a (passive) Nagios checker. It runs Nagios (or Icinga), checks on defined objects, and submits the results to a specified NSCA host.
Nagus is a Nagios filesystem for FUSE. It is a simple python-fuse application that reads Nagios' status.dat file and exposes that information through a filesystem interface.
A Live Linux distribution with a focus on education.
A program that displays global uptime records.