ka-doink, boink

A word/sound you use after someone says something incredibly obvious. Like using the word "duh", only way better. May be followed by a swift slap to the back of the person's, who pointed this obvious statement out, head.
Or sometimes its acceptable to use a face palm.

EX: "Hey, your wearing a green shirt!"
"Uhh Ka-Doink, Boink. Genius."
*swift slap to head* (optional face palm)