I remember the 20th anniversary splash page, and remember frequenting the site much earlier than that.
I ended up joining:
Date Registered: August 07, 2003, 11:10:03 pm
So, at the moment, I'm creeping up on 9 years.
I remember joining well before the marioguy explosion (which I actually added him on MSN a couple years ago), and I remember making a thread suggesting that TMK should have a chatroom. Some weeks later, iirc, they did end up incorporating that, though, I'm not saying I'm taking credit for the idea. I don't know if it was already in the works and I suggested it around that time by coincidence, or what.
I also remember being a half-op with Meowrik/Forest Guy long ago, but some BS went down with... hmm FrozenSolid/FrozenPantsSolid/whatever? I remember him pestering a lot of us for the longest time, and then all hell broke loose, and we were stripped of our titles.
Lastly..... hmmm, I think I was nominated or whatever for a post I made for the TMK Awards. I forgot who it was that voted for me, and I know it was for the "funniest/best post", but there's no way I'd ever remember what it was unless I wanted to dig it up.