Lilith is a logging and access event viewer for the Logback logging framework. It has features comparable to Chainsaw, a logging event viewer for log4j. This means that it can receive logging events from remote applications using Logback as their logging backend. It uses files to buffer the received events locally, so it is possible to keep vast amounts of logging events at your fingertip while still being able to check only the ones you are really interested in by using filtering conditions.
Observium is an autodiscovering network monitoring system focused primarily on Cisco and Linux networks but includes support for a wide range of network hardware and operating systems. Observium has grown out of a lack of easy to use NMSes. It is intended to provide a more navigable interface to the health and performance of your network. Its design goals include collecting as much historical data about devices as possible, being completely autodiscovered with little or no manual intervention, and having a very intuitive interface.
net-status-monitor is a simple console script to test whether Internet connectivity is working. If it is, the script tells you the external IP address (in case your dynamic DNS provider is down). If not, it tries to find the point where the connectivity fails. The output is quite simple, so you can put it on your grandmother's PC. "Just tell me what the read line says" should give you enough information.
Monjo is a Web application that helps monitoring a small to medium network of servers. It offers easy customization of notifications in case of network failures and is designed to allow for easy addition of new services that need to be monitored. It's internationalized and includes a Web interface in English and German. It currently supports notifications by email and can check services using ping, SMTP, HTTP, POP3, and IMAP4.
Treewatch watches a directory for a specified type of file to change. When one of the files changes, treewatch runs a program of the user's choice. By default, treewatch will watch the current directory and run "make" when changes are detected in files ending in .cpp, .c, or .h. The user can specify any number of directories to watch, any number of file types to watch for, and any command line to run.