Apr 19-25... according to a Youtube video from Kittle Coins... he says go to the ANA's website: https://www.money.org/ and click on the "Get a free gold membership during National Coin Week - learn more" pink-ish banner towards the top of the screen. If you don't see it, just refresh the page. Then go here: https://www.money.org/numismatic-events/national-coin-week and click on the "Zip. Zilch. Nada!" picture/link on the left. This is a no-brainer... right? Link to Youtube video by Kittle Coins: (I am not affiliated in any way, shape, or form with Kittle... or the ANA... at least not yet)
Thanks for the heads-up, @Dougmeister ! Just in case anybody else wants to know more about the benefits of an ANA membership: https://www.money.org/uploads/Public ANA Member Benefits Guide.pdf
As far as I know, this was sponsored by NGC. If you aren't an ANA member, there's absolutely no reason not to!
Plus you can request a free NGC submitter #, instead of having to join at the lowest (no grading voucher) level.