Suricata is an Intrusion Detection and Prevention (IDS/IPS) engine developed by the Open Information Security Foundation and its supporting vendors. The engine is multi-threaded and has native IPv6 support, file extraction capabilities, and many more features. It's capable of loading existing Snort rules and signatures, and supports many frontends through Barnyard2.
WormTrack is a network IDS that allows detection of scanning worms on a LAN by monitoring anomalous ARP traffic. This allows detection of scanning threats on the network without having privileged access on a switch to set up a dedicated monitor port. It does not require constant updating of the rules engine to address new threats.