If multiple players are instructed to scry at once, such as while resolving Eager Construct's triggered ability, those players each look at the top card of their library at the same time, then they choose in turn order whether to put those cards on the top or bottom of their library.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.