I have seen three sources that state that in order for governments to get people to eat potatoes they put guards on them and "let" people steal them - tricking them into thinking they were valuable. Is this an early urban legend or at some European conference the ambassadors were sitting around a table getting drunk and one said "Yeah, we tried to get them to eat those too. Here's what we did..."

Prussian potato: http://www.history-magazine.com/potato.html

French Potato: https://en.wikipedia.org/wiki/Antoine-Augustin_Parmentier

Greek potato: http://en.wikipedia.org/wiki/History_of_modern_Greece#Administration_of_Ioannis_Kapodistrias