There are several plugins available for FireFox that allow you to monitor instances of Nagios and notify you using colors and sounds if things are in specific states.
One such plugin is called Nagios Checker. OK state is green, warning is yellow, and critical is red. It also allows you to play certain sounds on specific events.
Another tool for monitoring Nagios instances is called Nagstamon (http://nagstamon.sourceforge.net/download/).
Nagstamon is a Nagios status monitor for the desktop. It connects to multiple Nagios, Icinga, Opsview and Centreon monitoring servers and resides in systray or as a floating statusbar at the desktop showing a brief summary of critical, warning, unknown, unreachable and down hosts and services and pops up a detailed status overview when moving the mouse pointer over it. Connecting to displayed hosts and services is easily established by context menu via SSH, RDP and VNC. Users can be notified by sound. Hosts and Services can be filtered by category and regular expressions.
