Ellis Island has a microbrewery (supposedly, I don't go there). There's a Gordon Biersch but that's not really a micro.. Sin City Brewing has two places one inside the venetian and one inside the flamingo. Most of their brews are forgettable though. If it were up to me, I'd be going to Big Dog's. It's the closest one to the strip and really good. It's on the corner of Sahara and Torrey Pines if you're interested (about 15 min from the strip).