Cleite is an RSS aggregator that is composed of a client and server. Once you place the server part on a host, you can read RSS feeds from various environments using the client part.
The server and client part are independent softwares: their implementations can be replaced. Currently the server is written in Scheme and runs on Chicken. The client is written in EmacsLisp and runs on Emacs.
% darcs get --partial http://ccm.sherry.jp/darcs/cleite
Sorry for non-Japanese speakers, the only documentation which is currently available is written in Japanese. English translation might be available in the future.
The documentation of Cleite is here.
Cleite is in the public domain. See the following page for more details.