My father's (on something that is useless): It's not worth the full of your arse of roasted snow.
On something that wasn't even close: It wasn't within a beagle's gowl of it.

Mine (to a heckler) Ok, who just got a delivery from Assholes "R" Us?

To a heckler: This is my job and how I make a living to support my family. When you're doing your job, do I follow you into the men's room and kick your kneepads out from under you?

To a heckler: Six million sperm, and YOU'RE the one that got through?

Seamus