Dynamic Ad-Hoc Routing Simulator (DARS) is a platform-independent simulator of mobile, ad hoc network (MANET) protocols. It is expandable and already comes with Ad hoc On Demand Distance Vector (AODV) and Destination-Sequenced Distance-Vector Routing (DSDV).
WhoisUP monitors hosts via ICMP and shows the status in a webpage. When a host is down, it can send mail, write a syslog message, open a popup message, or play a sound. It uses Nmap to check hosts continuously.