FreeBSD: I become an ardent FreeBSD user when we launched Gamespot.com back in 1996. It provided by far the most bang for your buck you could get for internet infrastructure. I started the SF FreeBSD Users Group, we held monthly meetings and it gave users a chance to hear directly from the core FreeBSD developers what they were working on and they, in turn, got to hear first hand how their wares were being put to use in production. I had to stop running the users group when my son was born in 1998 but I think it still lives on as the Bay Area FreeBSD Users Group.
I mostly use Linux now. Not 'cause I like it better but having a supported Java Virtual Machine and other things that can only really be kludged onto FreeBSD with Linux emulation is the real priority for me. I imagine someday I'll get back into BSD but it's gonna have a purdy face on it with a rainbox striped apple on it and it'll be called "OS X."
VRML: At one point in time, I really thought innovative 3D interfaces were going to emerge that would transform how we represent and interact with data. From about February to June of 1995 I worked with spontaneous gang of similarly intrigued folks on the Interactive Media Festival VRML ARC. The folks who I worked with on that moved on to launch Construct, a VRML focused internet design firm which went on to succeed with a number of innovative accomplishments. But then we all know what happened with VRML, right?
Still, I harbor a latent interest in the Java 3D API's and hope I'll someday have the free time to again dabble with that stuff.