I used Sanity to manage two collections of artworks that are being auctioned/sold in memory of a friend to benefit the Trans Justice Funding Project.
The biggest challenge was finding an online auction platform or payment gateway that didn't take tons of fees so we could get as much money as possible directly to the cause we're supporting. Oddly enough we ended up deciding to use eBay to handle the bidding and transactions, given that they take 0% fees from registered 501(c)(3) nonprofits.
When the auction "launches" at 6pm PST on 5/13, the countdown clock transitions to a "LIVE NOW" countdown to the end of the auction, and reveals a link on each item to the associated eBay listing. The clock is being controlled by two Datetime fields. Clean and simple!
