ServerSpy is a VB.Net based application that installs as a service and serves to monitor uptime and availability of other networked servers and web sites.
hammer is a Http load testing tool for Unix/Linux platforms. hammer reads scripts of XML that describe the load tests. hammer is implemented in C++ using Xerces-C and Commoncpp2.
TrUp is a client for the Uptimes Project as started by Wonko for the TriangleOS (http://httpd.chello.nl/w.cools) written in ANSI C without any extra libraries. Supports protcol 5.0.