According to Byteball's twitter feed they have posted a crossword on reddit and if you solve it and send it to them you will get some free Byteball coin.
Here is the link:
https://www.reddit.com/r/ByteBall/comments/7nxqqm/byteball_crossword_puzzle_solve_and_earn_5000000/
I assume this is legit since it is on their twitter feed but if it is not don't kill the messenger.