Foo Fighters know a thing or two about music festivals. They've certainly played enough of them. In the second year of the Foo Fighters-led Cal Jam, they've managed to create a top-notch event that's on par with some of America's top rock festivals.

Festivals are the perfect place to do a little something different, and Cal Jam jumped to the top of the news cycle Saturday night when Dave Grohl called upon Krist Novoselic of Giants in the Trees to join he and Pat Smear for a rare Nirvana reunion minus the late Kurt Cobain. To pull it off, he just reached out to Deer Tick's John McCauley, who was already on the bill, and Joan Jett, who was in town promoting her documentary Bad Reputation, (Jett performed with the band at their 2014 Rock and Roll Hall of Fame induction, and both Jett and McCauley performed with them at an after-party later that night). The Nirvana set came as the encore to Foo Fighters' performance, with McCauley handling "Serve the Servants," "Scentless Apprentice" and "In Bloom," and Jett singing "Breed," "Smells Like Teen Spirit" and "All Apologies."

Foo Fighters also made the festival special with a set list dedicated to the "old school" fans. Celebrating nearly 25 years since their debut album, Grohl doffed the traditional set list, which typically ends with "Everlong," in favor of celebrating each album in reverse, starting their set with "Run" and "The Sky Is a Neighborhood" and wrapping with "For All the Cows" and "This Is a Call." The set found Grohl taking a stroll in the crowd during "The Pretender," while the singer also introduced his mother Virginia to the audience during the song "Arlandria." During their performance Grohl and drummer Taylor Hawkins also marveled at what they'd pulled off with their festival, speaking of their love for rock music and the camaraderie with the acts on the bill. "This is a real fucking deal," stated Hawkins.

It's true. The Foo Fighters fingerprints were all over the festival, with Grohl in particular present onstage or at the side of the stage at several performances throughout the day. Giants in the Trees, featuring Novoselic, performed on the Mountain Stage earlier in the day, with Grohl watching from the side before eventually taking a turn behind the drum kit for a song. He could also be seen catching a bit of the highly energetic two-piece Slaves U.K. bringing the heavy on the Main Stage.

For the second year in a row, Queens of the Stone Age had a presence, with several members of the group joining Iggy Pop for a "Post Pop Depression" set. The ageless wonder Pop appeared thankful for the chance to play, bringing a "lust for life" of the bands half his age on the bill in the process. Favorites like "Lust for Life," "The Passenger" and "China Girl" populated the set and wowed the crowd and Pop's bandmates alike. Homme later introduced pop as "the legend teaching you stuff when you didn't even know you were learning."

Other Foo and Grohl associates also played a big role in the day, with Nirvana producer Butch Vig showing why his band Garbage remains a force with a stellar set on the main stage. Shirley Manson remains one of the fiercest frontpeople in rock, commanding the stage on fan-favorites "I Think I'm Paranoid," "Stupid Girl" and "I'm Only Happy When It Rains." They also offered a nod to Depeche Mode's "Personal Jesus" in the midst of opening track "No Horses." Tenacious D, featuring "Learn to Fly" video co-stars Jack Black and Kyle Gass, had the biggest side stage audience of the day while headlining the Sun stage. Their guitar-heavy performance included "Rize of the Phoenix," "Dio," "Tribute" and other favorites.

Other highlights of the day included Manchester Orchestra's blistering late afternoon set and Greta Van Fleet's mid-day performance, which showcased just how far the upstart rockers have come in a short time. Greta pulled in one of the biggest early day crowds, and with good reason. The licks and music have always been there, but they've made great strides as a live band in the year-plus since they first arrived on the national scene. There's a confidence that now comes with that booming voice and those killer licks. Meanwhile, Manchester Orchestra wowed with a ferocious performance including the aggressive "Shake It Out," their biggest hit "I've Got Friends" and the set-closing "The Gold."

Another key to a great festival is variety and the ability to turn fans onto new music. This year's Cal Jam succeeded in this aspect, with most of the acts having a base in rock but never feeling too similar. The mighty Thunderpussy opened the Main Stage amidst an overcast sky, setting the tone for the day with a commanding performance. Uniformly dressed in red, the ladies quickly grabbed the attention of the arriving crowd while vocalist Molly Sides mesmerized with her blend of physical grace and vocal power. Over on the Sun Stage, Kingfish delivered a mic drop type of set to start the day, with his blues licks causing the early day milling about among festival goers in the side stage areas to stop as music lovers immediately flocked to see who was behind those blistering licks. The guitarist won over fans mid-set taking his playing into the crowd, with throngs of fans following as he made his way through the audience all the way back to the VIP seating before returning to the stage.

Charlie Overbey and the Broken Arrows gave fans a more folky performance, highlighted by a stellar closing cover of Tom Petty's "Even the Losers." With stages right next to each other, Giants in the Trees captivated with the voice and stage presence of Jillian Raye, finishing out their highly attended and hypnotically mesmerizing performance only to have Yungblud provide the perfect contrast, kicking off the most energetic sets of the day. And female foursome FEA brought plenty of attitude and punk ethic to their performance. Simply put, Foo Fighters hit a home run with the sampling of lesser-known acts on the bill.

As Dave Grohl and company took their final bows, they thanked fans for their support and mentioned coming back next year. Here's to looking ahead to another great year of rock music. Check out our photo gallery for the 2018 Cal Jam below.

Cal Jam 2018 Photo Gallery