Five Crowns

Did you know that at some point in history, a deck of playing cards had five suits? In America, Bicycle used an eagle, across the pond they used a crown, and in today's featured game, the fifth suit is a star. Five Crowns is a rummy style game that's amazingly familiar to learn, while offering a tantalizing number of possibilities per hand.
How it works: While I don't play gin rummy, I find myself playing a lot of rummy-type games, and Five Crowns looks familiar. Players compete to complete melds, either books (three or more cards of the same rank) or runs (three or more cards in sequence (e.g., 3-4-5)). Of course, everyone at the table is hunting for the same cards, so pay attention to what's being played and discarded on each hand.
The goal is to "go out," playing your entire hand as melds on the table. Any player with cards left in their hand is penalized for their total (ala dominoes), and the player with the fewest points at the end of the game wins.
Why it's clever: The game starts slow and easy, with each player only receiving 3 cards. Then each new hand, players start with one more card. It's a nice, built-in mechanic to start friendly and ramp up the chaos as the game continues. Each meld has to be at least three cards, but there's no limit. You can string all your cards together, if fate allows it. There's also a really fun push-your-luck angle, because you can work on melds in your hand before you play them on the table, to be sneaky. But look out! Get caught holding cards at the end of the turn and you're going to pay for it.
Price: $9
Bonus: this is a popular one, so it's available in dozens of formats. Different designs, travel decks, metal tins, you name it.