Mustn't Brag but...
Basic Brag is a three card game.
With each hand you make various three card hands whose strength resemble hand strengths in poker.
Therefore the simplest version: three card Brag has hands described in ascending order as: High card, pair, flush, run, running flush, three of a kind.
Once people have understood the basic three card group, you get into larger hand variants.
Four or five card brag simply allows discards to get the optimum three card unit. Six or higher cards means you create sub-units of three cards and choose what order to play those units.
The fun of the larger hand variants is that you get great flexibility on what hands you choose to make. You choose in advance which order you want to play the hands you made. The skill then comes from balancing your hands to try to make sure you win the most three card rounds. One really strong hand...played...last? Or three more even hands?
A nice way to teach kids the basic idea of poker hands (without the vice of gambling!)