Squid Proxy - Website Content Acceleration and Distribution. Thousands of web-sites around the Internet use Squid to drastically increase their content delivery. Squid can reduce your server load and improve delivery speeds to clients.
CCProxy - Want to share Internet connection? Get every computer online through a single Internet connection?
Apache Traffic Server - Fast, scalable and extensible HTTP/S 2 and 1.1 compliant caching proxy server.
WinGate - WinGate is highly capable web proxy software for Windows: caching, intercepting, forward and reverse proxy with https inspection and SSL offload, SOCKS server, email
FreeProxy - Feature summary from website:* Internet connection sharing with demand dialling
gate.js - gate - Performance & scalable I/O forward & reverse HTTP proxy based on node.