privacyIDEA is a modular authentication server that can be used to implement 2fa with your existing applications. Can use many different back-ends, from LDAP to Active Directory to flat files. Has a self-service portal for users. Policies enforce different requirements on groups. Supports HOTP, TOTP, SafeNet, eToken Pass, Safeword, OTP cards, Google Authenticator, RADIUS, SMS one-time tokens...
Has a TokenClass which is designed for adding new authentication devices. Has a REST API. Plugins for many services available. Supports detailed audit logging. Supports multiple databases for its datastores. Database contents are AES encrypted.
Github repo: https://github.com/privacyidea/privacyidea
Open source captive portal software for setting up your own wireless hotspot.
Somebody cloned Portal into an open source game done entirely in ASCII. Cute.
CKAN is open source data management portal software for extremely large data sets, on the scale of entire governments. Used to publish, curate, share, search, and find datasets of just about any kind. Does visualization and metrics. Source code on Github (https://github.com/ckan/ckan). Written in Python, uses Postgres as its back end. Can interface with Apache Solr for search and indexing.
A daily weblog of the weird, mysterious, occult, and strange, with links all over the place.