OpenERP is a complete business application suite. It covers CRM, accounting (analytic and financial), production management (MRP), stock management, sales and purchases management, task automation, marketing campaigns, help desk, POS, and more. Technical features include a distributed server, flexible workflows, an object database, a dynamic GUI, an XML-RPC interface, and customizable reports.
StreetSign is a digital signage system, originally written for the TeenStreet 2013 (Germany) youth congress. It works with a single server, and multiple client computers connect over the network. It is lightweight enough that a Raspberry PI can run as the server for smaller installations.
modu is a high-level toolkit for building database-driven Web applications in Python. It provides all the common components needed to build custom Web applications in Python, including form generation, object-relational database mapping support, pluggable template systems, database-resident session and user support, and more.