Summer Sundae Weekender, De Montfort Hall and Gardens, Leicester

Summer Sundae is an unfailingly hip festival that requires few stars to draw a crowd. Supergrass and The Coral pass for big pop here, likewise new reggae name Natty. Roisin Murphy dwarfs her thumping electro-rock with a head-banging sweater girl persona. Reverend and the Makers' Jon McClure is similarly hands-on in making his crude take on the Happy Mondays connect.

More typical are mavericks such as Hammill on Trial, aka Ed Hammill, a middle-aged bald American who approaches rock'n'roll as stand-up. "Why Go Halfway?" is about the whoring of integrity, a message eased by confessing he's "self-righteous... with a big mouth, preaching to the choir". Henry Rollins' spoken-word set teeters on messianic self-regard, but his convincing wish for us to become a community fits a festival with more activists' stalls than sponsors.

Jeffrey Lewis strikes a similar chord with his covers of songs by UK anarchists Crass, but isn't quite at his best. Joan As Police Woman belts out a set recalling the singer's punk past, while retaining the bereft ecstasy of "Jump the Ride". Nina Nastasia sings austere country in a withdrawn voice sheathing disturbed emotion.

These wild Americans are matched by Frightened Rabbit, whose ferocious rock songs of leprosy and sex reduce singer Scott Hutchison to a hollow-eyed stare. Fellow Scot James Yorkston is a more touching spectacle, a series of small mistakes leaving him clutching his broken-stringed guitar like a failed comfort blanket. Rachel Unthank and the Winterset's folk doesn't stretch the form as he does, but brings it to gracious life. Wild Beasts' baroque falsetto indie, preppy Danish experimentalists Efterklang and the shrieking oscillations of Paris's Zombie Zombie all draw good, curious crowds.

But Saturday's headliner Macy Gray steals the show. Dressed like late-period Ella Fitzgerald, she plays Radiohead's "Creep" as a soul song of defiant acceptance, then follows it with "Do Ya Think I'm Sexy?", which I'd like to see Thom Yorke try. "I Try" is expanded into a 20-minute leviathan swallowing scraps of everyone from Cab Calloway to John Lennon, while retaining its heart. Watching the crowd grin and sing to this free spirit, pop's point seems in the air.