The Ninja project is an attempt to develop an alternative Nagios GUI with the aim of being the most useful Open Source Web front end for Nagios. It improves searching and filtering and scalability. It supports templates and skins for customizing appearance, and supports several databases. You can use the components of Ninja in combination with the CGI scripts of the original Nagios Web GUI or as replacements for them.
openpom is a Web interface based on NDO for Nagios or Icinga. It allows you to view almost everything about Nagios or Icinga in a single page: alert, ack, downtime, comment. You can also interact with Nagios or Icinga through ack, downtime, comment, disable, and reset buttons. You can filter on hosts and services states (such as critical, warning, unknown, ok, or outage). The status popin allows you to display graphs, either the ones from Nagios (trends.cgi) or custom ones based on RRD (such as pnp4nagios).
SpurTracer is a push-notification based monitoring solution for heterogenous loosely coupled IT infrastructures. It complements a service-endpoint monitoring solution like Nagios with a component-level interface auto-discovery. It automatically provides a certain level of functional tracing along with many non-functional measurements (e.g. call, error and timeout rates, interface latency, component execution, etc.). While being zero config itself, SpurTracer relies on you adding push notification support to the components you want to monitor. The best way to use SpurTracer is by adding punctual tracing to components in your infrastructure on-demand.