Opus tokens have been listed today on Etherdelta!
There are a few sell orders with the price close to the ICO, so if you didn't participated in ICO it's a chance to buy them at a good price right now.
You can check their website to know more about Opus foundation here:
And you can buy or sell the tokens for the moment here on etherdelta. I don't know if they are listed on other exchange yet and I dont think they are listed on coinmarketcap also. They were listed this morning on etherdelta.
https://etherdelta.github.io/#OPT-ETH
Happy trading everyone!