Monitoring::Spooler is a handy queue manager for queueing and delivery of monitoring notifications. It is able to handle several groups of on-call personnel and provides an extensible plugin mechanism to connect it to virtually any remote service which provides some kind of API. It is designed to work nicely with App::Standby.
snmp4zabbix provides a simple SNMP interface to the Zabbix monitoring solution. This lets Zabbix monitor itself using the Simple Network Management Protocol. This is an alternate solution to the Zabbix API for integration, to some extent, with any third party software capable of understanding SNMP.