52 Card Pickup (or sometimes written as Fifty-Two Card Pickup or Fifty-Two Pickup) is not so much a game as a practical joke or prank played on an unsuspecting recipient or recipients.
The prank is usually performed by one individual, who is aware of the prank and one or more others who are not. The prankster then takes a full deck of 52 cards in hand. In order to add to the prank, the prankster may shuffle the card or re-arrange the deck as if preparing for a legitimate card game. However, once the cards are shuffled and in a neat stack, the prankster will then toss the cards into the air such that they fall in a jumble of cards onto the floor. He then shouts something such as "I throw the cards, you pick them up!". The recipients of the prank are then left to re-assemble the deck from the cards which have been scattered all over the floor.
Although that is the entirety of the prank, some individuals do sometimes make it into somewhat of a game, by modifying it into a contest to see which player can pick up the most cards, or challenging everyone to find a certain card or attempt to collect all cards of a certain suit in the fastest time possible.