rss aggregator

There are a few rss aggregators which I like:

However, none of them quite match my needs. Trawlr is nice, but I want
the data in my own db so that I can work with the data if I like.

The straw project is nice, but they're not using rails conventions.

Finally, feed-on-feeds is closest to what I want in that it aggregates
feeds using standard LAMP (in this case, PHP). However, I like rails, so
basically would like to clone/redo feed-on-feeds using rails.

So, I started:

Having a better grasp of how to use the relationships thanks largely to
this list, I feel more capable of tackling something like this.

However, the primary concern is how to populate the database. I don't
mean putting some data into the migrations, or even loading data with
SQL, but grabbing feed data from the internet.

How would I use something like:

to grab feeds?