I just have to say again, everyone is cracking me up!
My family that I grew up in finds farting quite funny- don't know why, but we just have that silly sense of humor I guess. My husband does not- he thinks that is a private matter that is embarrassing. And this is from someone in the military! So, whenever I joke with the kids about farting, or something of like ilk, my DH just says, "You guys and your strange sense of humor" and shakes his head.
Two things that my kids have done recently that made me-

my older DS wanted a whoopie cushion, so I got him a 4 pack of little ones I found at Target and my mom found him a regular sized one. He stacks them up to sit on them all at once and comments, "Hey, if I farted for real at the same time as the whoopie cushions, it would be an UNSTOPPABLE FART!"
My mom and I were laughing so hard we could not catch our breath!
And then, we watch Shrek too much; I think it's from Shrek anyway. If one of my boys rips a good one, I sarcastically say, "Nice!" Not pardon me or excuse you. Nope, I am teaching them great manners.

So, now when they toot, I'll say "What do you say" and they say, "nice." And crack themselves up. And this is like when we're out in public, not just at home!!!!!!!
Oh, and the story where someone's boyfriend (now DH) would be the gentleman and open/close the car door for his girlfriend and rip one outside the car- yeah, my DH did that too when we were dating. All I could do not to BUST UP laughing!