Blizzard has quite the impressive itinerary for this year's gamescom. there are planned events for each day, spanning from quizzes for prizes, their costume contest, live drawing sessions from Blizzard artists, live concerts, dev signing events, Heroes of the Storm live shoutcasting matches, contests and events in several of Blizzard's games and the WoW: Warlords of Draenor cinematic debut and release date reveal. their schedule can be found here.
according to eu.battle.net , there will be hour-long live streams each day on August 15 - 17. they will air on August 15 and 16 at 9 am PDT / 12 pm EDT and on August 17 at 7 am PDT / 10 am EDT.
they have a gamescom event page at us.blizzard.com/en-us/company/events/gamescom-2014.html. also, if you want to follow the Blizzard conversation on social sites, they are using the #BlizzGC2014 hashtag.