2DaT has released Obxd, a free virtual analog synthesizer instrument for Windows.
Obxd is emulation of famous ob-x, ob-xa and ob8 synths.
While not copying originals, some of the features were taken to a better point.
32 and 64 bit versions included.
The plugin is a free download at KVR Audio.
More information: 2DaT Obxd