mainline copypasta v0.1

I also hear people ask a lot what Touhou is and how to get into the series if you're new to it.

Touhou is a series of vertical arcade style shmups, with a few official fighting games.
The simplest way to break into the series is to download TH6 or TH7 and start playing, they can be found here: http://artifactgaming.com/moriyashrine/officalGames/TH6.7z
http://artifactgaming.com/moriyashrine/officalGames/TH07.7z

If you're interested in the characters, background or setting, there is a wiki full of information about every aspect of the series here: http://en.touhouwiki.net/wiki/Touhou_Wiki

If you're not into shmups or fighting games, there are also many official mangas that portray the characters and world well, and can be found here: http://moriyashrine.weebly.com/official-print-works.html

Finally, Touhou has a huge, dedicated fanbase that produces a lot of great content, particularly music remixes and fangames.
Many great fangames are linked here: http://moriyashrine.weebly.com/spinoff-games.html
And there is a huge jukebox with a ton of remixes here: http://touhou.kuukunen.net/