Since that fundamental shift, such amphitheaters wove themselves into the suburban summer template. The kids saw the second-tier pop acts, the teens went to Lollapalooza, Warped Tour and Ozzfest and the parents hired babysitters for their big night at the James Taylor or Earth, Wind and Fire show. With many of these places right off the highway, it was a quick exit on and a quick exit off (parking lot traffic not withstanding). But as a few recessions, a dot-com bubble and a housing crisis took their toll and turned the happy, sweaty, crowdsurfing kids into weary, wary, tightwad adults, the concert industry felt the pinch. Even almost half a decade after the start of the recent financial crisis, it's tough to get folks to come out to shows anymore. According to Billboard, global concert grosses and attendance each fell 10% last year, with concerts in North America alone drawing 6% fewer people than they did in 2011. Even Billboard admits the damage is likely far worse, as numbers have been much tougher to get since they took a nosedive in 2010 and companies such as Live Nation ( LYV) cut back on reporting their attendance and income figures. the first six months of 2013 are down from the same period last year, according to Pollstar. That said, it's still been a big year for amphitheaters. Of the 20 top-grossing concerts in the U.S. so far this year, according to Billboard's Boxscore, five have been shed shows. Country stars deserve the bulk of the credit, as Brad Paisley and Rascal Flatts shows in Virginia, Indiana and Ohio took up four of those five spots. All of those shows were at Live Nation venues, which should please the ticket giant that was taking a bath at this time three years ago. The fact that The Black Keys and Flaming Lips could crack the Top 20 in the U.S. and Top 50 in the world with a shed show in South Carolina -- at a tiny 13,400-seat venue, no less -- says a lot about the potential of a summer shed circuit that already includes a Bob Dylan/Wilco double bill, Black Sabbath, Blake Shelton, John Mayer, Fun., Bruno Mars and Queens of The Stone Age. While some suburban staples such as the metal-heavy Mayhem Festival and the '90s flashback Goo Goo Dolls/Matchbox 20 bill remain, the shed circuit has embraced diversity similar to the neutral-site festival circuit that's sprung up around it in the past decade or so. As fests such as Bonnaroo, Lollapalooza and Outside Lands have grown, the sheds' pool of big, available acts has drained. That leaves amphitheaters with two options: Start festivals of their own, as the Gorge Amphitheater did with Sasquatch! In 2002 and the Paradiso dance fest last year, or take the best of what's left. What they can't do, however, is pretend they're the only game in the outdoor concert business anymore. By learning from past mistakes, booking wisely and knowing their rapidly evolving audience, even the most utilitarian sheds can be great places to take in a show. Keep tacking on charges for customers and trotting out milquetoast lineups, however, and festivals and a growing number of alternative, urban outdoor venues may force amphitheaters to fold up the tent. -- Written by Jason Notte in Portland, Ore. >To contact the writer of this article, click here: Jason Notte. >To follow the writer on Twitter, go to http://twitter.com/notteham. >To submit a news tip, send an email to: firstname.lastname@example.org.