I mostly find the odd places when searching on and for discussions of old stomping grounds. That usually leads me down a long path of links. Sometimes I discover by joining oddly named and sparsely visited IRC rooms. Occasionally great sites are posted to 4chan.

A recent discovery was made when looking for recent references to Temple Of The Screaming Electron. This search led me to two weird corners (potentially NSFW).

1. http://www.popeye-x.com/title123.htm As far as I can tell originally set up by a group of programmers (and I think phreakers, digging through the archives ), based in Texas with a common connection to a niche Austin based radio station. Highly original, deeply buried links, multiple hidden forums.

2. http://nobodytm.com Not even sure how to explain this one! Has a chat room that the owner sometimes frequents with cryptic messages that appear to mean something to other participants.

I was trying to find a subreddit to help promote a friend's video when I found this and now check it every day:

https://www.reddit.com/r/DeepIntoYouTube

The rules are something like < 1000 views in six months. So it's all obscure stuff.

Strange subreddits are good. StumbleUpon isn't useful for much, but permitting tons of categories and going wild with it is a good way to get weird.

Anything that allows chaining is a big help, which is why people get to "the weird part of Youtube" more easily than the weird parts of the general internet. Sometimes you can exploit this by dipping in and out of linkable things (it's like recreating webrings). Try following chains of linked subreddits or tumblr accounts, then popping back out at some odd-looking link they point to.

But honestly, it's hard. I find a lot of 'weird internet' by reading the SlateStarCodex link collections, and otherwise letting other people do the hard work for me.

Data-mining reddit is often a good start.

reddit serves some very narrow niches and outlinks to some very curious places.

Sometimes people will deliberately manufacture an experience like this for a creepy story/etc, which can be fun.

Internet mythmaking in general ('creepypasta'/etc) is a fun rabbit hole to go down. Most are mediocre, but a handful of stories are genuinely brilliant:

http://creepypasta.wikia.com/wiki/Psychosis

http://thebooksofsand.blogspot.com/