Telize is a REST API built on Nginx and Lua which gets a visitor's IP address and queries location information from any IP address. It outputs JSON-encoded IP geolocation data, and supports both JSON and JSONP.
RRDA (RRDA REST DNS API) is a REST API that allows you to perform DNS queries over HTTP. It supports PTR records for both IPv4 and IPv6 addresses and outputs JSON-encoded DNS responses.
A daemon which implements the PPP protocol for internetworking over dialup lines
An interactive Web spreadsheet allowing concurrent table editing.