Here's a rundown of what we're given.

[url=http://example.com]Click Me[/url] -> Click Me!
[url=http://example.com]               -> http://example.com
[img=http://example.com/flower.jpg]      (Nicer syntax)
[img]http://example.com/flower.jpg[/img] (Alternative syntax)
[center]Stuff[/center]
[centre]Stuff[/centre]
[i]Hello[/i] -> Hello
[b]Hello[/b] -> Hello
 [u]Hello[/u] -> Hello
[s]Hello[/s] -> Hello
[indent]Hello[/indent]
--- 
[quote=Mahz]Hello[/quote] (Named quote)
[quote]Hello[/quote]      (Unnamed quote)
[hider=My Spoiler]Some secret stuff[/hider]
[list]
[*]Item A[/*]  (Yeah, need the [/*] for now)
[*]Item B[/*]
[*]Item C[/*]
 [/list]
[list=1]
[*]Item A[/*]
[*]Item B[/*]
[*]Item C[/*]
[/list]
[youtube]GRbD4g3hshw[/youtube] (http://www.youtube.com/watch?v=GRbD4g3hshw -- Just the code after the ?v=)