There's a couple of free events next weekend (23 Feb 2013), one in Glendale, California, and the other in Indianapolis, Indiana:
Glendale's Mystery and Imagination bookshop, where Bradbury used to have his public birthday parties, is hosting readings by members of Bradbury's own theatre company. Here are the details:
Meanwhile in Indy, the Center for Ray Bradbury Studies' director Jon Eller will be speaking about Bradbury at the Irvington branch of the Indianapolis Public Library.
Details of the event are here.