I usually do it like that. Sometimes I like to alter my response. This would be a set a responses I sometimes use.
"Ah, I get it. You're one of those weird people." *turns away*
*facepalm, turns away*
"That was clever. Did you come up with that all by yourself or did you read it somewhere?"
*stares for 2-3 seconds, turns away and ignores*
"That's great, dude." *disinterested voice tone*
"Good for you." *disinterested voice tone*
*disapproving light shaking of head and turning away*
"Please don't start crying on me now." *turns away*
"Is that what your mom/girlfriend said to you?"
The main trick is to NOT use a condescending tone. The more you show that it is not triggering an emotional in you, the more impact your reply will do. You probably noticed that I use a lot of non-verbal cues.