Web-based Process Visualization (SCADA/HMI/Dashboard) software

A full functional WiFi Repeater (correctly: a WiFi NAT Router)

Unofficial api documentation and web interface to control "Daikin Emura" air conditioner

Browser mapping solution for Open GPS Tracker

OpenTracker - open source GPS/GLONASS hardware

LED Strip control over HTTP using an arduino (w/ Android & Windows apps)

An interrupt driven Arduino library for the DHT22 temperature and humidity sensor

Use Dreamhost as a DynamicDNS provider (for your Tomato or DD-WRT route, for example).

Web-app for processing, logging and visualising energy, temperature and other environmental data

Arduino HTTP library

Arduino IDE 1.x