Did you ever needed to show a content of a PDF file in your Joomla page? No, I don't mean link it to be downloadable, but actually show it!
Until recently the only way to do it was DocMan, with a specialized plugin capable to show preview of the PDF files available for download. Was a solution... but to show one or two files was an overkill. Recently I had this problem again, and invested a serious amount of time to find this marvel:
Enbed_pdf is a plugin for Joomla 1.5 and Joomla 1.7 to do exactly that: show pdf files on your Joomla webpage! This plugin inserts easily your pdf files on your page. You can decide to show your pdf with Google viewer, or the users locally installed acrobat plugin. If you decide, to use Google's viewer, as an added benefit you can use it to show not only PDF files, but Microsoft PowerPoint presentations and TIFF files too! Highly recommended!