These are the standard published rules, rewritten in plain words. Hearts is a backwards game: points are bad, and the low score wins.
Hearts is a trick-taking game where you are trying not to win certain cards. Every heart you take costs you a point, and the Queen of Spades costs you thirteen. The winner is the player with the lowest score when the game ends.
Players: 4 is the classic game (Bicycle's rules also list versions for 3 to 6, with cards removed so the deal comes out even). Ages: 8 and up.
What you need: one standard 52-card deck. Cards rank Ace high down to 2 low. There is no trump suit.
Shooting the moon — how it is scored: The two standard references print it differently, so here are both, labeled. Bicycle's rules: the shooter scores zero for the hand and each opponent adds 26 points. Britannica's rules: the shooter chooses — either subtract 26 from their own total, or add 26 to everyone else's. Pick your book's version before the game.
Omnibus Hearts — the Jack of Diamonds bonus (labeled variant): In the popular Omnibus variant, the player who takes the Jack of Diamonds scores minus 10 points — a prize instead of a penalty. Britannica notes some tables use the 10 of Diamonds instead of the Jack. Everything else plays the same.
Passing patterns: The left–right–across–hold cycle is the standard. Some computer versions and house games pass left every hand, or drop the hold hand. The printed cycle is the one above.
Does the Queen of Spades break hearts? Not in the standard game — only a heart discarded on another suit breaks them. A few house games count the Queen as breaking hearts too. That is a house rule.
The 2 of Clubs must open: Standard rule, not optional. The first trick is always started with the 2 of Clubs by whoever holds it.
Can I lead the Queen of Spades?
Yes. The ban is only on leading hearts before they are broken. Spades, including the Queen, may be led at any time.
I won a trick with hearts in it by accident. Do I have to take the points?
Yes — points in tricks you take are yours, wanted or not. That possibility is the whole game.
What if I take all the hearts but someone else took the Queen?
That is not shooting the moon. You score your 13 hearts and the other player scores the 13 for the Queen, as normal.
Can hearts be played on the first trick if I have only hearts and the Queen?
Yes — the exception. A player whose hand is nothing but penalty cards may play one on the first trick, having no legal alternative.
Sources: Bicycle Cards, "How to Play Hearts" (bicyclecards.com/how-to-play/hearts), and Encyclopaedia Britannica, "Hearts" (britannica.com/topic/hearts-card-game). Read in full and rewritten in our own plain words. Where the two disagree — shooting the moon — both versions are printed above with their sources named.