Gin Rummy

Goal: Be the first to 100 points over several hands. You each hold ten cards.

Your turn: draw one card — from the deck, or the top of the discard pile — then discard one, so you're back to ten. You can't throw back the discard you just picked up.

Melds: group cards into runs (3+ in a row of the same suit, e.g. 5-6-7♠; Ace is low) and sets (3–4 of the same rank, e.g. three 9s). Cards left over are "deadwood": Ace 1, J/Q/K 10, others their number.

Knock: once your deadwood is 10 or less, knock instead of a normal discard to end the hand. Your opponent may lay off their deadwood onto your melds, then you score the difference between your deadwood and theirs.

Gin: knock with 0 deadwood for their deadwood + 25 bonus (and no laying off against you).

Undercut: if their deadwood ends up equal to or lower than yours, THEY score the difference + 25.

Deck runs low: if it gets down to two cards with no knock, the hand is a wash — no score, redeal.