The market for tree stumps has never been better, as a drinking game called hammerschlagen - German for hammering nails - gains popularity at tailgating parties. The trendiness was boosted even more by an appearance on the Jimmy Fallon show, and a front page feature in the Wall St. Journal.

Players encircle a tree stump, whose top is crowned with lightly sunk nails. Rules require players to catch a hammer tossed by another contestant and try to sink the other player's nails, complicated by the fact it is done beverage in hand. If they hit the nail, they take a drink. If they hit the nail flush, they finish their beer. Whoever has the last nail standing wins.

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The game was patented March 19 by Marc Johnson and partners (Patent No. 9,295,906) under the name MöbileSchlägen (as described here):

A collection of game pieces including a block and a support tray. The block includes a top surface, a first width and a thickness. The support tray includes a top surface, a bottom surface, a second width, a depressed portion on the surface and the support tray is adapted to removably receive the block centrally on the top surface. The ratio of the first width and the second width ranges from about 6:7 to about 1:2 such that a flange of the support tray is formed. The block is configured to receive a plurality of nails driven into it using a striking tool and if the striking tool accidentally misses the block while used in driving a nail into the block, the flange is used to arrest the striking motion of the striking tool.

Advocates for the game tout its advantages over Frisbee tossing and beer pong, since it is unaffected by wind conditions, and more grown up.

"Unlike Beer pong or flip cup that may seem to immature or 'college' to the older crowd, stump is a more 'refined' and 'manly” game that may attract the 'college bro' but also the hardcore tailgater who’s been been at every game since the Cowboys first won the Superbowl,"  Clayton Gray and Brendan Harder say at ther website. The Rochester Institute of Technology graduates launched The Stump Company and a Kickstarter campaign to supply the market.

Unsuccessful in meeting its investment goal, the The Stump Company was stumped by state requirements that businesses confirm shipped wood is free of invasive pests. And the weight of stumps - full sized might be 200 or 300 hundred pounds - brought shipping charges way up.

Johnson's MöbileSchlägen eliminates the weight issue by selling just a four-inch thick slice of wood. Their patent spacifies that the "block includes a material having a density of from about 20 to about 40 lbs/ft.sup.3. In one embodiment, the block includes a material having a Janka hardness of from about 350 to about 550. The material can include natural wood, a glulam, Medium-Density Fiberboard (MDF) and Urethane Foam Board."

The game is typically played with a cross-peen hammer or blacksmith's hammer and a large (24-36'') cross-section of a soft hardwood, Johnson says. "Cottonwood is suitably soft for this game."

Another entrant in the field, Jim Martin of Lake Elmo, Minnesota, operates Hammer-Schlagen competitions and awards, and claims the rights to the trademark.

Martin also franchises the game for operators at $5,000 to $10,000 each for a five-year contract. To help protect his trademark, Martin created the Hammer-Schlagen Society, which maintains and verifies records of competitions.