If you thought Microsoft’s multi-million dollar Cirque du Soleil backed introduction of Kinect, its gesture-recognition controller, was extravagant, you ain’t seen nothing yet.Activision, publisher of such games as “Call of Duty: Modern Warfare 2,” “Guitar Hero” and “World of Warcraft” reached into its coffers and pulled out what might have been the most extravagant party in the video game convention’s history. That’s saying something. Two years ago, MTV and Harmoix (makers of the “Rock Band” game franchise) brought “The Who” to the gaming nerd-vana for a set that lasted well over two hours. In the show’s heyday, Sony would spend millions for luxurious events on its lot, with performers ranging from Beck to Foo Fighters. Not content with one artist — or even two – however, Activision hosted its own Lolapalooza-like event, filled with artists from its “Guitar Hero” and “DJ Hero” games — as well as those who have contributed to other upcoming games. DJ legends Z-Trip and Deadmou5 warmed the crowd up at the Staples Center Monday night — with VIPs and media housed in the sky boxes. After a short while of their mixes and a cavalcade of dancers mimicking Lady Gaga as “DJ Hero” was announced to the crowd, the show really kicked into overdrive. Usher was the first artist on hand, belting out hits such as “I Want to Make Love” and “Yeah!”. His four-song set seemed as bit short, but he ended up being one of the hardest working acts of the night — even bringing out Will.i.am for a number at the end. Jane’s Addiction hit the stage for two songs before calling it a night, while Soundgarden performed just one — “Blackout Sun”. The crowd didn’t seem to mind, though, cheering the escalating number of performers. Pharell Williams and N*E*R*D were next, followed by Williams’ protégé Rhea, who performed just a single song. After a short intermission featuring a pole dancer — wearing a bikini — the main act hit the stage. For the second consecutive year, Eminem took over the Activision stage masterfully, holding the crowd in his hand, with a backup gospel choir and surprise appearance by Rhiana. Activision is the richest company in gaming — and has the money to burn. But the largess shown at this year’s presentation brings to mind the E3 of five years ago, when publishers were spending uncounted millions to outdo each other. Those were the good days, economically speaking, and the show still nearly collapsed. With revenues down sharply, it makes one wonder if the escalation wars are about to kick off once more — and if anyone else can afford it.