Have the same problem. Could be the Apple TV, could be our two iPhones or the iPad, could be my Airport Extreme, could be the two Airport Express stations interfering, could be the neighbors Wifi networks interfering.
Check if your are using channels that are used by your neighbors. Move your Wifi router a foot or two. Check if there is anything else interfering. See if one of your devices is faulty.
I am selling my second gen Apple TV and ordered the 3rd gen Apple TV. Since there is a free iTunes gift card I almost get the same price for my used device on eBay. 🙂 Our two iPhones are getting replaced by two new iPhones 6 so maybe this will help. And if my problems keep coming back I am changing my Airport Extreme next.