Gamescom kicks off this week at the Koelnmesse convention center in Cologne, Germany, with its annual stage show, Opening Night Live. Taking place Tuesday, August 25, and hosted by Geoff Keighley, the event is the second of the three annual Keighley showcases (along with Summer Game Fest and The Game Awards) that will feature two hours of video game trailers. Expect to watch world premieres of new titles and updates for previously announced games. Here’s where and when to catch…