Custom Content Page with Code

Scenario:
You want to add a new custom Content Page with some code. You have two different choices to do that, inline code or code behind.

Recommended:
Go for Code Behind. Content Page lives in SharePoint Content Database and can be customized using SPD. Inline script will only work when the page is uncustomized, but once it is customized, SharePoint's safe mode parser will block the page from being executed.

Article:
http://www.andrewconnell.com/blog/articles/UsingCodeBehindFilesInSharePointSites.aspx