You might have heard about chaince, a centralized exchange foucusing on the EOS ecosystem, that recently airdopped their tokens.
If not, have a look at one of my recent posts on the airdrop
One thing that has remained obscure to me, is how the staking mechanism would work. I asked in their telegram, annd they prommised a detailed example and video tutorial, and finally, here they are:
https://medium.com/@Chaince/roadmap-of-chaince-c3e4a1e30e5e
To sum it up, if you stake your chaince tokens, you will get a weekly payout of your share of 50% of accumulated trading fees in EOS.
Only if you want to unstake you need to return all received EOS. I believe this is similar to other new exchange concepts, and the Maker/DAI function, that 
Although that sounds really cool, according to their current roadmap staking will only be possible from around October.
Of course all that depends of the ETH/EOS pair trading volume, this is currently at 60EOS / 24h which equals about 28K$. This is not huge and far away from the big boys, like binance, bitfinex, etc. but still not unremarkable.
If more tokens get listed, this could evolve pretty quickly.