well bitpost 30 wasn't a competition between eachother per se, it was more a competition for the self. setting the commitment and then following up with that commitment.
I think relay should similarly do a daily mint, can be artistic, can be a blogpost, at the end everyone who did a daily has their mints added to a collection.
I propose a relay club challenge similar to the Bitpost 30 day challenge. My 30 Gold NFT doesn't have any util, but it commemorates something cool that I worked for so it's one of my favorite NFTs.