An eye on your system
pg_activity is a top like application for PostgreSQL server activity
Tool to ping hosts through firewalls blocking ICMP
Scalable, distributed monitoring system for high-performance computing
Highly configurable SNMPv1/v2c/v3 application-level proxy
Network performance monitoring and logging script for Cisco devices.
nagios-statd patch for use with python >= 2.6
A flexible, extendable content filter