To my knowledge smash brewing is where you use one grain and one type of hops to make a beer. you keep it simple so you can gain knowledge of how each grain and hop affects the different attributes of the beer. I did one a while back with Saaz and with pale 6 row, pretty drinkable session beer.
"I feel sorry for people who don't drink. When they wake up in the morning, That's as good as they're going to feel all day."
- Frank Sinatra-