Recently I was updating the list of measuring-related online games & resources at my site. I found these resources (new to me) and thought you might enjoy them a:
The Ruler Game
Choose between whole inches, half-inches, quarters, eighths, or sixteenth parts of an inch to measure. Click on the given measurement on a ruler. Timed or not timed versions available.
Sal's Sub Shop
Customers order subs, and you need to cut them to the given measurements - sometimes in metric units, sometimes in inches.
You can illustrate a variety of measuring devices, such as scales, measuring cup, thermometer, and speedometer, and how to read them. Generate examples using different scales on different devices at the press of a button.
An online activity about metric measuring units and how to read scales, measuring cup, and a ruler. Uses British spelling.
I have a longer list here: Measuring - list of online games and tutorials.
Of course, with measuring, life and experience is the best teacher, not computer games. So encourage your child/students to play with measuring cups, scales, and rulers so they will learn to use them.