LInk parkin': I was doing my bimonthly search for pieces of the Emacs of Aggregators (TM) and ran across:
rawdog is an RSS Aggregator Without Delusions Of Grandeur. Written in Python, it uses Mark Pilgrim's feed parser to read RSS 0.9, 1.0, 2.0, CDF and Atom feeds. It runs from cron, collects articles from a number of feeds, and generates a static HTML page listing the newest articles in date order. It supports per-feed customisable update times, and uses ETags, Last-Modified, and gzip compression to minimise network bandwidth usage.
curn:
Unlike many RSS readers, curn does not use a graphical user interface. It is a command-line utility, intended to be run periodically in the background by a command scheduler such as cron(8) (on Unix-like systems) or the Windows Scheduler Service (on Windows).
Rawdog is conveniently written in Python, but curn's plug-in mechanism looks more polished, taking advantage of Java metaprogramming. If you just want to monitor a pile of feeds and don't need megascale performance, these might be a good place to start.