If you want to display some code on a wiki page, blog post or even in comments, use the code macro.
To insert the macro, type "{code" and then hit return when "code block" is shown in the auto-suggestion pop-up. A code block will be added with your cursor flashing in it ready for you to paste in the code.
After adding your code, be sure to click on the code block and then "Edit" to change it's settings:
< choose the relevant language for syntax highlighting
< enter a title that gives some idea what the code is doing
< show line numbers
< choose the "ecplipse" theme (all the others are grim IMHO)