Polipo - A small and fast caching web proxy (a web cache, an HTTP proxy, a proxy server).
memcached - High-performance, distributed memory object caching system
Artica Proxy - Artica Proxy is an appliance that claim to manage Squid-cache proxy with all features that Squid...
Skytable - Skytable is a free and open-source realtime NoSQL database that aims to provide flexible data modelling at scale.
Privoxy - Privoxy helps users to protect their privacy.
Dragonfly DB - Dragonfly - Scalable in-memory datastore made simple