We made GNU social which had its part in starting the Fediverse! GNU social was a spin-off from GNU FM, which was the software we made to run Libre.fm -- Libre.fm has been federated for a very, very long time.
Monkey movies and stuff also happened. See https://orangumovie.com/
Anyway, we're back, kind of. Libre.fm needs code for the next 15 years and we're here to write it once more. If you're interested, ping @mattl