Ruby Toolbox - Explore and compare open source Ruby libraries
Alternato - NOTE: Not available in English.
AlternativeTo - AlternativeTo lets you find apps and software for Windows, Mac, Linux, iPhone, iPad, Android, Android Tablets, Web Apps, Online, Windows Tablets and more by recommending alternatives to apps you already know.
AlternativePedia - Discover free, open source or simply better alternatives for your software based on our research...
UserBit - A full-stack qualitative research platform for UX & product teams.
Aventrix - Aventrix is a website that helps you discover new and fun activities.