Freebie from FXpansion...
Check this out. A free monosynth from our good friends at FXpansion. Marketspeak: "Orca is an experimental monosynth built to showcase some new technology that FXpansion has been developing. Based on detailed and accurate models of analogue synthesizer circuits and components, Orca excels at deep, squelchy basses and thick unison leads."
In real life: I haven't tried it yet, but it looks fly, and they're trying to get some feedback on a new synthesis method (which is almost certainly some old synthesis method.) It's sort of creepy looking, like an alien vagina or something, the Rubber Johnny of user interfaces. Registered FXpansion members only; you just have to create an account, then you can get the synth. Grab it http://www.fxpansion.com/index.php?page=12&tab=60>here.
UPDATE: I've just spent a few minutes with it. It has a distinctly ARP-ish sound; it actually sounds really good for software. Not much you can program (
amp filter env, freq and res, and some detune shit) but incredibly usable sounds. Definitely give it a try, unless you're an Intel Live user; Intel Live doesn't load VST2.3 plugs, which this is.