RSS aggregator for student blogs

The students on the Module "Internet Applications Development" which Rob Stephens and I teach are required to write blogs during the year.  Enthuiasm for this aspect of the module is somewhat varied but we have undertaken to keep up our own reading of the blogs and encourage students to read each other's blogs. 

Students have chosen a number of different blogging platforms to use and we have a blog roll on the Module wiki.  However reading each to see if anything has been added is tedious.  This is obviously the role of RSS. Personally I use Blogspot as an aggregator but I want the students to easily  read the aggregated blogs too.  So I rolled-my own basic system in XQuery on the eXist database.

The user view of the blogs is a sortable listing (using sorttable.js of course).

The feeds are cached by a second script which is scheduled by the Quartz scheduler in eXist  to run every 2 hours but can also be refreshed on demand, for example prior to a session reviewing blogs.

This application required a total of 80 lines of XQuery. I'll post it on the wikibook when I have a moment.  I looked for but couldn't find a function to convert from RFC-822 dates in RSS to  xs:dateTime  - must have missed it.