What is "mumblety peg"

Mumbledy peg \Mum"ble*dy peg`\, Mumblety peg \Mum"ble*ty peg`\, n. A game played with a pocketknife, the object of which is to throw the knife in any of a vairety of ways (such as over the back), or from various positions, and have it stick in the ground or another surface. Also called mumble-the-peg and mumble peg.

n. (context US English) Any of several forms of a game in which a jackknife is thrown so that it sticks into the ground close to the player's feet.