By default, Sputnik uses Niklas Frykholm's implementation of Markdown Syntax. (Other markups are possible: see Markup.)
Here are some of the basics of Markdown markup that you can use with Sputnik:
Links
Wiki Links: [[Architecture]]
External Links: [a great site](http://www.greatsite.com)
Emphasis
Bold: **some text** (__some text__ also works)
Italic: _some text_ (*some text* also works)
Headers
H1: don't use this on this wiki
H2: ## Header or underline the header with ------, e.g.
Installing on Unix
------------------
H3-H6: ### Header, ### Header, etc.
Code
Code Blocks: indent the code by four spaces, e.g.
foo = function() return nil end
Code inside the paragraph: surround the code in back-ticks, e.g.: `foo()`
Note, however, that if you want to display your whole page as if it was code, set it's
"actions" field to {show="wiki.code"}, rather than indenting the whole page.
(Indenting everything works too, but that's silly.)