The market keeps on moving: SAP acquires Sybase etc. But one name attracted my attention: GemStone being acquired by VMWare/SpringSource (next to RabbitMQ, Hyperic, ...).
Time flies: I remember Gemstone as a vendor of OODBMS and application server. On the OODBMS side there were also Versant, ObjectStore (eXelon --> Progress). The list of applicaton servers - just before EJB's took off - is much longer: Netscape Applicaton Server, Forté, Jaguar CTS (Sybase), Tengah (became WebLogic), IBM Component Broker, ATG Dynamo, Novell Silverstream, Novera, ... Had forgotten about most of them. Another such "hidden" company that I recently encountered is Pramati.