The ongoing parade of concerts in and around the capital this summer includes several rock festivals, the biggest of them all – in terms of duration, number of acts and ambition, if not quality as well – starts tomorrow at the Olympic Baseball Arena in Hellenikon, southern Athens. A six-day event, the Gagarin Open-Air Festival brings in a diverse cast of leading acts, from still-relevant veterans to bright contemporaries. They include Iggy & the Stooges, Calexico, Kaiser Chiefs and Mudhoney. The Gagarin Open-Air Festival, a summertime event organized by the winter-season club of the same name, follows hot on the heels of this year’s Rockwave Festival, an 11-year-old event whose earlier indie-rock leanings have gradually given way to a hard-rock/metal agenda. It was exclusively that this year, with Metallica bringing the three-day event to its end last night. As for the Gagarin Open-Air Festival, Iggy & the Stooges headline the opening night, tomorrow, not long after the legendary proto-punk act followed up a reunion tour with a new album. Released this year, «The Weirdness,» the first album of new material by the Stooges in over three decades, emerged as a logical step following a triumphant return to the stage in 2003. Though frontman Pop and his old bandmates Ron Asheton and Scott Asheton did recreate the riotous sound of their early period for the reunion tour, the ensuing new album, produced by Steve Albini (Nirvana, Pixies, Dirty Three) differed greatly. It caught the critics by surprise and has received mixed reviews, which, of course, probably mean little, if anything at all, to Pop, an enduring, dedicated and real rock’n’roll animal, now 60, and his reunited bandmates. Also on the festival’s worthy agenda tomorrow are grunge-era pioneers and survivors Mudhoney, as well as the Soulsavers, featuring Mark Lanegan, the charismatic, big-voiced former frontman of another grunge-era band, Screaming Trees. For Friday, the event’s organizers have put together major domestic drawcards, including Yiannis Angelakas & the Episkeptes, the reunited Last Drive, Diafana Krina, and cult attraction Lost Bodies. Headlining next Tuesday, Calexico, a refreshing addition to the contemporary scene with considerable reliance on old-school sounds, including country, mariachi-Mexican, and punk-surf, rank as a highlight. The band’s drummer John Convertino, one of the act’s two core members, spent years providing the beats for the ultra-alternative and long-lasting project Giant Sand, fronted by Howe Gelb, a gifted yet fiercely uncompromising musical figure. Through its ranks, Convertino found a fertile artistic partner in Joey Burns. Working as the rhythm section, chiefly on bass and drums, for Gelb’s criminally neglected Giant Sand, Convertino and Burns gradually realized there was potent enough chemistry for musical activity of their own as a side project. Calling themselves Calexico, the pair’s debut effort «Spoke» hinted at a worthy direction, but it was not until the follow-up, «Black Light,» that they achieved a coherency capable of attracting a wider following. And it did. That was back in 1998 and since then, Calexico have gone from being appealing unknowns to one of the healthier aspects of the musical establishment. The band had passed through Greece last summer, but skipped Athens for shows in Thessaloniki and on Crete instead. This time, the return is for just one show, in Athens. Gagarin Open-Air Festival: Tomorrow – Iggy & the Stooges, Mudhoney, Soulsavers featuring Mark Lanegan; Friday – Yiannis Angelakas & the Episkeptes, the Last Drive, Diafana Krina, Pavlos Pavlidis & the B-Movies, Dinos Sadikis, Lost Bodies; Sunday – Paradise Lost, Type O Negative, Rotting Christ, Opened Paradise, Sun of Nothing; July 9 – Kaiser Chiefs, the Long Blondes, Good Shoes; July 10 – Calexico, Sophie Solomon, Beirut, A Hawk and a Hawksaw; July 11 – Joe Satriani and special guests.