Plain HTML (with neither CSS nor JavaScripts). Any fancy PHP or other things might usually be unneeded; you can just write them plainly, which is easily enough.

Plain HTML (with neither CSS nor JavaScripts). Any fancy PHP or other things might usually be unneeded; you can just write them plainly, which is easily enough. I might also have NNTP for discussions/blog/comments/announcements, Telnet/SSH for interactive sessions (if any are needed, which it might not be), etc.