SAP is one of the ERP behemoths that dominates in the enterprise world. Pretty far removed from Rails? Not really, it turns out. Piers Harding has written a great article for the SAP Developer Network that shows how to create a Rails application that uses a SAP backend as the model instead of Active Record.
The article shows how to use SAP4Rails with two BAPI objects – Currency (BUS1090), and ExchangeRate (BUS1093) – and make those available through a standard Action Controller setup. Very cool stuff.