Radius is a free platform for running local groups and events, pitched as a Meetup.com alternative — groups take “60 seconds” to set up, and the homepage feed already carries real ones, from a Nevada County D&D group to a running club in Shipston-on-Stour. Its new beta feature, Activities, drops the group requirement: post something as loose as “a cycle and a coffee in New York at 10am” and let people vote on a time instead of RSVPing. Built on Rails; this relaunch follows a Show HN from June 2024.