Many moons ago, there existed a bunch of packaged applications for Apex on the Oracle website.
Alas and alack, they were removed and all that exists in their place
is a collection of sample code. They'll be making a comeback in Apex 4.2 where they will be 'prepacked' in the installation and ready to install. You can keep them vanilla, and perhaps get some support from Oracle for them (or maybe just an upgrade path), or you can unlock them and make your own customisations and enhancements.