I wonder how well a memory foam mattress pad would work as a sound deadening barrier for my door... I can hear literally everything going on in the living room, and it is damn tiring being woken up early EVERY DAY by one of the dog's freaked out yelping every time she's left alone for 2 minutes. ESPECIALLY when there's a 3 AM bathroom break for the dogs.
But yeah, I have two of the things from when I was sleeping on a futon that turned out to be not nearly as comfortable as I hoped.