The Internet Archive
Notes: The most useful thing on the internet, to date. Millions upon millions of websites and profiles have been archived here. Some things remain intact, while code and script updates mangle most pages of the olden days, but the Wayback machine remains one of the most useful tools ever. They also have a lot of good movies, books, music, and TV shows to torrent.
Wiby
Notes: This search engine shows you websites that haven't been viewed in the past decade. There are a lot of neat things I've found, some disturbing, but mostly funny and even useful.
Palace Chat
Notes: An old style IRC chat client that lets users upload any image as an avatar with up to 9 frames for gifs. There are lots of people on here who remember the old way of things. I'm trying to start a revival of people using it. This website links you to where to download it. Just pick a username, put some avatars in your prop bag and have fun becoming God!
After The Beep
Notes: A site that has a number you can call and leave a voicemail that will be approved and published. I really like the layout of it as well. The coding is awesome and it's a very unique idea for a website. Very active even recently and seems like a good place to vent.
Bloody Pulp Fiction
Notes: A website that seems to be someone's horror passion project, accompanied by some images that look almost like a reskin of Doom? Very interesting stuff, nonetheless. It advertises a game for the PC, but I haven't tried to install it. Still the visuals are interesting and it was the first site I came across from the old net that fits my vibe. So I'm putting it here :)