Pull My Finger just has four buttons; labeled Fart 1, Fart 2, etc. The audio quality is decent, but what happens when you need to customize the fart for a certain situation or person? Bah! Get Noble Fart! Which is, if anything, noble. It features a pretty interface with a great graphic, and six, count 'em SIX different farts - each represented by a button emblazoned with a descriptive title: "Wet, Deep, Long, Blow, Airstart, and (my personal favorite) Special." The app is free until 2075.
Search the market for "fart" and let 'er rip.
Both apps function well and feature fairly faithful faux flatulence for your funny. O.K., O.K. I'm done for the day.