I vote for 03/Jan/2021 ...
the same date in 2029 would be the perfect one, I think, but a bit too far away for me.
There is no way that you can just make a "Stop Hodling" day. People get to do what they want and if they want to keep their Bitcoin, so be it. You don't see anyone going around saying "Stop Hodling fiat". Why? Because it is just outright stupid. People are allowed to do what they want with their Bitcoins, whenever they want to. The point of a decentrallized currency is to put the power in the hands of the people using it. They are their own bank, no one can take their money away from them.
I know that I won't stop hodling for a long time to come. And I am pretty sure there are a lot of other Bitcoin investors out there who also won't