This puzzle consisted of the hearts and spades from a deck of cards. Each was labeled with a letter of the alphabet and an instruction. In order:

8S A Move cards to the bottom of the deck until an ace or face card is on top.
3H B Keeping this card on top, perform a perfect riffle shuffle.  Then discard this card.
2H C Place the highest ranking card in the discards on the bottom of the deck.  Then discard cards until a card of the same suit as that card is on top of the deck.
4H D Discard a number of cards equal to the number of high card points the bottom card of the deck is worth in standard bridge scoring.
8H E Swap this card with the next card in the deck of the same suit.
2S F Swap this card with the first card in the deck with a vowel on the corner of its label.
JH G Discard cards until you have discarded enough cards to bust in blackjack.
7S H Sort the cards in alphabetical order by the letters on the corners of their labels.
7H I Discard all cards with rank less than the rank of the lowest-ranked discarded card.
KH J Reverse the order of the top five cards in the deck.
6S K Swap this card with the first card in the deck such that, after the swap, the top five cards in the deck beat two pair.
QH L Discard this card.
5S M Discard the highest five-card poker hand you can assemble with the cards in the deck.
TS N Move cards to the bottom of the deck until a red card is on top.
JS O Discard three cards, then arrange the remaining cards in reverse order of the letters in the corner of their label.
AH P Discard cards until the top card of the deck is outranked by the bottom card.
QS Q Discard any card whose instructions end in the word "deck".
5H R Swap the top four cards in the deck with the bottom four cards, preserving their order.
9H S Among the cards you have discarded, find the one whose instructions have the fewest words.  Discard a number of cards equal to that number of words.
AS T Alternate between discarding a card and moving a card to the bottom of the deck.  Stop immediately after discarding any red card.
KS U Discard this card.
TH V Discard this card and any other card in the deck that has the same rank.
4S W Move cards to the bottom of the deck until an ace or face card is on top.
9S X Discard ten cards.
6H Y After discarding this card, sort the remaining cards by the number of words in their directions.  Your answer is given by the letters on the corners of their labels.
3S Z Move this card to the bottom of the deck.

Also included was a joker bearing the label A Deck Conundrum and these instructions:

Set this card aside, then follow the directions on the top card of the rest of the deck. After you do that, follow the directions on the card which is now on top of the deck, and so on. If you make a mistake and want to restart, note that each card has a letter on it, and the cards begin in alphabetical order.