>>2
Install and configure Tor (or just use the Browser Bundle) and hit up core.onion:
http://eqt5g4fuenphqinx.onion/
Good place to bookmark since it hosts no content of its own, but only links to other sites (whose pseudodomains shift around a lot). From there go to TOR Directory and find a website that takes your fancy. Image boards are a pretty common format for hidden services, so you should feel at home using them.