Korean slang

Slang I've heard from Koreans in the last few days.
Translation, anyone?

멍 때렸어
seems to mean that something "went over my head" or "I was out of my mind for a few minutes" ....(I've been warned not to use this phrase....so I will write it 100 times until I memorize it)

먹을 복이 있다
You seem to be lucky about showing up when it is time to eat.

썰렁 하다
Your joke was so bad that you froze the room.