Slack - A messaging app for teams who see through the Earth!
Cuba - Cuba is a Ruby microframework for web development.
Ramaze - Ramaze is a very simple and straight-forward web-framework.
Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.
Scorched - Scorched is a generic, unopinionated, DRY, light-weight web framework for Ruby.
NYNY - A (ridiculously) small and powerful web framework.