If anyone tells you that Deep Purple’s Concerto for Group and Orchestra (1969) wasn’t a masterpiece then they’re an idiot. In fact, it was, more or less, the only successful use of an orchestra with a rock band ever. Now, 40 years on, a pensionable Purple have hit the road again with a full symphony orchestra. But they’re not playing the Concerto. They’re playing their hits. Critically, they’re performing them without founding keyboardist, Jon Lord, and guitarist, Ritchie Blackmore.

Can the Hanson brothers ever rid themselves of the shackles of “MMMBop” (the 1997 hit that brought them global renown)? More to the point, should they bother to try? These were the burning questions I armed myself with as I prepared to watch a band whose progress, it’s fair to say, I’ve hardly followed in the last 15 years since their falsetto singing and rambunctious head-banging brought the world such joy. So, having done some serious mugging up, and listened to their back catalogue, I was interested to see where fortune would have taken the clean-cut trio with the flowing blond hair.

Boy, do Arctic Monkeys move fast. There were 21 songs in their set at the O2 Arena last night and at one point they were racing through them at such a breathtaking lick I thought I would be on my way home within the hour. In the end their performance clocked in at around the length of a football match thanks to some pauses to swap guitars. Plus a break for Alex Turner to stand by the drums and ostentatiously comb his elaborate quiff.

It’s a long time since I laughed during a show as much as I did in this one. And not, I hasten to add, in a snarky, narky, sarky way, but simply because it was fun. In another illustration of just how deeply competitive the business of the arena pop show has become, Britney Spears’s Femme Fatale tour is a formidable song-and-dance spectacle, with a full complement of dancers and hydraulics and epic visuals, and one that also features some damn fine music. But what makes this one memorable is that it's sexy and silly in equal measure.

In the 19 years of his million-selling gangsta-bragging pimp-shizzling hip-hop-rapping career, the man born Calvin Cordozar Broadus, Jr has gone to some lengths to inform us that his name is, in fact, Snoop Dogg.

Some bloke called Jack mailed to say that he did indeed have two tickets to Iron Maiden (baby), and for the Friday ‘n’all. So I called shotgun, threw on my cleanest “I ♥ Justin Bieber” T-shirt,* and pitched along to Docklands to hang out with the other teenage dirtbags – only to discover that they are, on average, actually about 40 years old. A lot of them in chinos.

Last weekend ballerina Tamara Rojo performed to the largest live audience ever to watch the Royal Ballet, at London's O2 Arena. But what was it like facing 12,000 people, and trying with her partner, the Cuban star Carlos Acosta, to tell the intimate story of two young lovers in Kenneth MacMillan's Romeo and Juliet? She tells us it's a weirdly out-of-touch experience on that vast stage, almost like being in private. And thank goodness for the cameras.

The Royal Ballet says it is inviting a new audience to experience the thrill of live ballet by taking Romeo and Juliet to the gigantic O2. Beware what you wish for. It’s the thrill of the live audience I’m starting with before I get onto the splendid show. Sweet packets rustled behind my ear, fish and chips were wolfed nearby, pizza shared, drinks slurped. People were still entering in droves 30 minutes after the start, obstructing the view of Juliet’s first scene. People were late back for Act II, triumphantly bringing the beers and crisps in, better late than never.

Jerry Seinfeld, acclaimed New York stand-up and star of the eponymous American sitcom co-created with Larry David, last performed in the UK 13 years ago. He’s currently doing a brief European tour and, while keen fans were quick to snap up tickets at the O2 in London, there were noticeably bare areas in the vast arena last night. Lots of British comics have managed to sell out the O2 (some repeatedly), but those unsold seats should come as no surprise; ticket prices started at £75 and went up to an astronomical £300, so the burning question must be - was he worth it?

Explosions, 40ft flames, light shows and back projections. It may have been at the Dome but at times it felt more like being in a music video. A mini-film opened the concert. Rush circa 1973 were boys called Rash, and they’d play only when professor Alex Lifeson operated his music machine. The contraption also had a button marked “Time Machine”. When pressed this catapulted the band, on stage, back and forth through their 37-year career. Every time the trio played songs from a different era, screens announced the year.