I've started using the DCI technique outlined in Jim Gay's book 'Clean Ruby'. To me Jim's technique is somewhat similar to the Hexagonal Rails approach describ

I've started using the DCI technique outlined in Jim Gay's book 'Clean Ruby'. To me Jim's technique is somewhat similar to the Hexagonal Rails approach describe in another comment. The DCI technique is to use the model as a persistence layer, and organize business logic into modules organized by use cases. With this technique my system has become much easier to understand and test. Its great to see people experimenting with architecture styles like DCI and HexRails.