The concert series runs through Aug. 28 with what organizers say is the most varied lineup they've ever had in the 21 years the series has been running.

"This is the first year we've brought in hip-hop artists," said Casey Jarman, concert series director with the Salt Lake City Arts Council, which runs the series. "We've put together a series that is as diverse as possible."

The Roots are perhaps the best-known act in the concert series. The influential Philadelphia band, featuring the innovative drummer Questlove, brings live instrumentation to hip hop. The band is touring behind its latest album "The Rising," which peaked at No. 5 on the Billboard album chart.

In addition to hip hop, the genres range from bluegrass to indie rock, and from old-school hip hop to folk rock.

Folk rocker John Ritter performs July 17 fresh off an outdoor appearance at Illinois' famous downtown festival, the Taste of Chicago. He said he and his crack band, which has been together for a decade, love free outdoor shows in the summer.

"Everyone is always in a good mood," Ritter said about outdoor audiences. "And it's a great way to reach people who haven't heard of you."

Ritter said his goal is to show fans and newbies alike he isn't a "bedroom folkie, wearing a sweatshirt and sipping tea." He added: "If I'm not drenched in sweat at the end of a show, I haven't done my job."

The first tip Jarman gives to people interested in a show is to get there early. At some of the most popular series last summer, up to 10,000 people showed up.

DAVID BURGER can be reached at dburger@sltrib.com or 801-257-8620. Send comments about this story to livingeditor@sltrib.com.

Things to know about the Twilight Concert Series

- It's first come, first served beginning at 1:30 p.m. You must be present at all times to reserve seating. You can bring blankets, and only low-backed chairs are allowed.

- The Twilight Market is open from 5 to 10 p.m. with various food and beverage vendors. Coolers are allowed, but outside alcohol or glass containers are not allowed.

- Beer and wine are available for purchase throughout the evening at specific locations.

- Service animals are welcome, but otherwise pets are not allowed.

- Paid, underground parking is available at One Utah Center/Gallivan Center. Metered parking is free after 6 p.m. The nearest TRAX stop is Gallivan Plaza at 239 S. Main St. For bus and TRAX information call 888-743-3882 or visit www.rideuta.com.

- Concerts are held rain or shine.