Example of a real-life graph with a "hole"? Anyone ever come across a real non-textbook example of a graph with a hole in it?  
In Precalc, you get into graphing rational expressions, some of which reduce to a non-rational.  The cancelled factors in the denominator still identify discontinuity, yet can't result in vertical asymptotes, but holes.
Thanks!

A car goes 60 miles in 2 hours.  So 60 miles/2 hours = 30 miles per hour.
But how fast is the car going at a particular instant?  It goes 0 miles in 0 hours.  There you have a hole!
It is for the purpose of removing that hole that limits are introduced in calculus.  Then you can talk about instantaneous rates of change (such as the speed of a car at an instant), which is the topic of differential calculus.
