Remember NVIDIA teasing something on its GeForce Facebook page last week? Well, today NVIDIA has posted an update that points to a countdown clock on GeForce.com. The company will unveil something at GeForce LAN / NVIDIA Gaming Festival (NGF) 2012 in Shanghai, China on April 28th. The countdown will expire at 7:30pm PDT that day, so you can keep it tuned right here for all the details. NVIDIA will live stream the event on GeForce.com and I imagine quite a few people will be wondering just what is being cooked up. The graphics giant has also sent out some crowbars to various websites with the words "For use in case of zombies or..." with the GeForce logo afterwards. Maybe the crowbar will have to pry open a container from NVIDIA containing a new product, like the rumored GTX 685 (GK110) or GTX 690 (dual GPUs). Whatever the case may be, we have until the end of the week for the speculation to come to a close.