Alaveteli
easy FOIA requests for any jurisdiction
Brimir
an email helpdesk
CodeTriage
directory of open-source projects with open issues
Danbooru
taggable image board
Discourse
next-generation discussion platform
Email Dashboard
email suite for marketing and CRM
Feedbin
open-source feed reader for multiple platforms
GitLab
self hosted Git management
huginn
open-source IFTTT
libraries.io
open-source discovery service
lobsters
link-aggregation site, inspired by Hacker News
OpenProject
project management system
Postal
mail delivery platform for incoming and outgoing e-mail
rubygems.org
The Ruby community's gem hosting service
samson
Web interface for deployments
sharetribe
Marketplace platform
TagTeam
social tagging for academics
TaxonWorks
workbench for biodiversity informatics
Terrastories
geostorytelling
va.gov
API for va.gov
zammad
enterprise-ready helpdesk and customer support system