Air 'n Sun was a free public BBS, reachable only by modem, that I ran from 1988 to 2001, in northern Virginia. I started it using hardware on loan from my erstwhile employer, Mead Data Central (now separated as LexisNexis). At first, I called it TIDMADT (These Initials Don't Mean A Damn Thing). I had thought this up long ago (about 1980), mainly to use as a car license plate or company name. I used it the first way from 1986 to 2002, and the second for the first few months of my failed attempt to be an independent consultant, from 1990 to 1992.
It carried mainly forums (Usenet newsgroups, Fidonet echoes, and non-shared message areas) and files on topics of interest to me. That includes Mensa, investing, firearms, Judaism, medievalism (i.e., the Middle Ages), OS/2, Linux, and a few more. However, I gladly picked up other forums that I could get for free or cheap, and other forums for the few donors. This offset general overhead, the costs of the forums on the main topics (which can be used for free), and of course the costs of the donor forums. There was also a Main area, where any topic was welcome.
People of all ages, sexes, races, beliefs, interests, etc. were welcome, as long as they behaved. Agreement was not necessary, but civility was. Aliases were allowed (except the names of real live famous people). Any topic could be discussed, but outright pornography was forbidden. (I am no prude, but didn't want to deal with the potential legal hassles.) So were commercial advertisements, except in forums where they are of special interest and within the forum's own rules, or by other special arrangement.
It was primarily a message BBS, but there were also some online games, and a decent selection of files on the primary topics, plus a few areas of DOS and OS/2 utilities, and a few other files.
It was in Fidonet (address 1:109/120) and a few specialty networks, such as Keshernet (Jewish) and Paul Revere Net (Second Amendment activism). Though not on Internet directly, it also carried a few gated newsgroups and mailing lists. It mainly ran Maximus 2.02, on one line, under OS/2 Warp, using Squish and BinkleyTerm for Fidonet operations. Early in 2000, I upgraded to Linux, still running Maximus under dosemu, but never got it to understand that it was communicating over a serial port. This meant no offline reading, and no games.