Inmusic Festival, Lake Jarun, Zagreb

"What's wrong with this bloke?" The Streets' bare-chested Mike Skinner berates the burly, naked Croatian man he's cajoled on to the stage who is taking perverse pleasure in refusing to crowd surf during the heart-rending "Dry Your Eyes".

Finally the unclothed man does. It's a rowdy moment, and it's a raucous festival at Lake Jarun. The previous day Arcade Fire's singer, Win Butler, descended into the crowd, only to emerge, shirt ripped, and visibly perturbed. It's giddy.

Butler delivers the statutory, "it's a beautiful city, we love it here", but you get the impression he means it. It is. Cypress Hill echo this sentiment with "Zagreb has really good weed, and really hot chicks", before launching into their hedonistic anthem "Insane in the Membrane". The veteran rappers have always been a ludicrously entertaining festival act – and the stench of skunk hangs in the air as they launch into the dynamite "When the Shit Goes Down" and "Hits from the Bong".

In comparison, Nick Cave's side project, Grinderman, is an angrier, growlier business. Even the legions of Mastodon fans here are left reeling from Cave's brutal, lewd odes to sexual frustration, most notably "No Pussy Blues". Warren Ellis – Cave's loyal cohort, sporting a Captain Caveman beard – performs his deranged roly-polys across the stage, at one point lying on the floor, legs up like an overturned dung beetle. Grinderman are wild, dangerous middle-aged men thrashing out their crises with gleeful venom.

However, the highlight is Arcade Fire. Butler's indie-rock outfit are arena-fillers now – and very adept ones too. Here they add a bit of disco and punk ("Month of May") to their routine. But it is the joyous finale of "Neighbourhood #3", "Rebellion (Lies)" and the dazzling "Wake Up" that leave us euphoric.