Hackathon: https://github.com/kleros/hackathon/issues/1
My submission (DApp example): https://github.com/genesisdotre/kleros-ethereal-virtual-hackathon
I need to improve the compliance with Arbitrable standard, this is the latest resource: https://erc-792.readthedocs.io/en/latest/ (already linked from the initial post)
Another DApp example is Realitio: https://realitio.github.io/