From the Website:
What is Haymaker!?
Haymaker! is an APAzine about Champions (a super-hero roleplaying game) and the rest of the Hero System (a generic role-playing game), and was founded in 1992. It is a collaborative effort of many different authors, and is a proving ground for many story ideas, characters, mechanics, general rules, or whatever the contributors want to write about.
What is an APAzine?
An APAzine (zine, for short) is an Amateur Press Association magazine. It is a group of like-minded people who write (or draw) on or about a specific topic (in this case, the Hero System). An APA works as follows; each member contributes an article by the deadline, delivered to the Coordinator. The Coordinator combines these articles into one publication, indexes them, and distributes the publications so that each member will receive a copy with every member's work (including their own).
Haymaker! is not for sale through any normal channels. You must contribute or know a contributor to see or get a copy.