How can output cache be enabled in SharePoint Foundation?

Question

I am using SharePoint Foundation 2010 and would like to enable output caching for certain pages, or maybe the whole site. On SharePoint Server you have a mechanism to enable page output caching across the site collection (it is actually ASP.NET output cache under the hood). On SPF you don't get that feature - fair enough.

So how can I enable output caching? In ASP.NET I would just add a page directive - something like <%@ OutputCache Duration="30" %>. SharePoint throws an error if this is in the page. Sounds like it needs to be done in code, perhaps override the page class? Any suggestions welcome.