Followup.cc - FollowUp for email is a lightweight productivity suite that keeps your conversations and tasks from slipping through the cracks. Set perfectly timed reminders that arrive at the top of your inbox, right when you need them.
CMake - CMake is an open-source, cross-platform family of tools designed to build, test and package software.
Streak - Manage customers inside Gmail
SCons - SCons is an Open Source software construction tool—that is, a next-generation build tool.
NetHunt CRM - Turn Gmail into a smart CRM
Ninja Build - Ninja is a small build system with a focus on speed.