I'm making this primarily for the Forum Tutorial Master List. These are just the basics, so if you want to expand on something in your own tutorial please do!

Displaying an image (in a post, profile page, or signature)

Code:

[img]IMAGE URL HERE[/img]

Linking an Image to a page (must put http://)

Code:

[url=http://URL HERE][img]IMAGE URL HERE[/img][url]

Code:

[center]Text Here[/center]

Colorful Text

Code:

[color=COLOR]TEXT[/color]

Scrolling Text or image

Code:

[scroll]Text or image here[/scoll]

Spoiler

Code:

[spoiler]Text here[/spoiler]

Embedding a YouTube Video

Code:

[youtube]VIDEO PAGE URL[/youtube]

I love you for embedding Bohemian Rhapsody.
Points x999999 for you. <3

<3 I thought you might like that.