It’s here, it’s new, with a much higher level of broness than slacklining.
Meet SuperSlack.
First – why slacksports at the Winter Not At OR? Cuz G1 is stuck with some serious hey-that-Al-Gore-guy-may-be-on-to-something weather:

Nice weather. For Florida. Or Frog Boiling.
So The Guy(s) hit the No-Sno Demo at the Old Highway 49 Bridge spanning the South Yuba, and gave SuperSlack, the new rage in dude-check-this-out sports, a ride.
So what’s the diff? Slacklining is slack, but SuperSlack cranks it to the next level by taking every shred of tension out of the line. The SuperSlack dude told The Guy(s) that, “The slacker the line, the tougher the traverse, so this is the most extreme slackosity we could achieve. Bro.”
By leaving the line limp, this “extreme slackosity” is achieved. The Guy(s) admired the simple genius of this innovative new technology. “Simple, dude” commented G1. “Genius, bro” commented G2 between bites of bacon.
The Guy(s) were suitably impressed. First thing The Guy(s) noticed was the set-up: super easy. A superslackline only needs to be anchored on one end – a second anchor would only add tension and decrease the integrity of the line.

SuperSlackline Ready for Action. Limp to the Extreme. Just like - never mind.
G1 hopped up and started his ride.Wobbly at first, thanks to the couple – or 3 – Four Lokos G1 had for breakfast, G1 quickly found his stride.
Both The Guy(s) noted that the learning curve is pretty, uh, slack – picking this up is quick, making it attractive to newbies as well as long-time slackers.

Sweet SuperSlacking, Bro. (PS @TNF: The shirt's just for fun. Please don't sue. Thx.)
Safety issues do exist – for example, with only one anchor point, the slacker needs to be aware of where the line lies (see figure 1).

Fig. 1, bro: Just Cuz It's Slack, Don't Mean It Ain't Dangerous - Always Look Where You Lay Your Line Before Stepping On.
Extreme slackosity means the line has a mind of its own. This is a sport that relies on gravity, and gravity can hurt.
But The Guy(s) noted that – once one gets the hang of it – this is a fun, safe sport that only requires minimal attention. Just like driving.

SuperSlacking while Texting? Cake. Hell, You Can SuperSlack While Drinking a Four Loko. Just Like Driving.
The Guy(s) were so enthused they decided to go into business. While ordinary (and soooo Summer Market 2009) slackline kits hover in the $75 – $150 range, The Guy(s) are selling their new superslick SuperSlack kits for only $50. Cash or check. And there’s the NoShow Special: free shipping for all orders placed at Not At OR, bro.