Hac Phi, a yearly weekend of Haskell in Philadelphia, will take place Oct. 21–23, 2016, at the University of Pennsylvania. Hac Phi is a gathering of hackers and Haskell enthusiasts. Come bring a project you’re working on or offer to help someone else on a project of theirs. Come give a talk if you’ve got something to share. Come to learn something new. What do we mean by a “Haskell Exchange”? Less pressurized than a hackathon, more informal than a conference, bigger than a meetup – Hac Phi is a weekend where academics, professionals, and hobbyists can all meet, mingle, hack on each others’ projects, and generally have a good time. (And it’s not to be confused with *the* Haskell eXchange, an entirely different event.) All the details are on [the wiki page](https://wiki.haskell.org/Hac_Phi); please [register online](https://goo.gl/forms/XXTxKFYAryVTjlgo2 https://goo.gl/forms/XXTxKFYAryVTjlgo2) if you’re coming. We hope to see you there! —The Hac φ team Antal Spector-Zabusky Kenny Foner