Hey all, Chia just announced that they're launching their second competition.
$50,000 to the team that optimises their verifiable delay function to be as quick as possible.
There will be two winners, fastest with hardware specific assembly optimisations, and fastest without.
Here's the blog post announcing it:
https://www.chia.net/2019/04/04/chia-network-announces-second-vdf-competition-with-in-total-prize-money.en.html

Their last competition paid out without a hitch, and they've published a BLS-signatures library on their GitHub, so these guys are legit.
You can check out their GitHub (which has a good amount of documentation and their reference implementation) here:
https://github.com/Chia-Network/vdf-competition