The Boston Guide has a few macros that aren't in the general distribution. The most interesting of these is a macro to create links to Flickr images from [[Image:FlickrID]] links.
It requires some mucking with configuration to set up a flickr key and flickr secret -- these come from Flickr when you sign up for an API key.
The diff between svn and boston's OpenGuides::Utils are attached. These are things that I will attempt to eventually clean up and get into the main tree, but right now they're just hacks, and may cause problems. No warranty or support, etc. etc., but if you want help getting something working, you can reply on-list or privately and I'll try and help you out. (Might even motivate me to clean up my code.)