Well Adafruit have just come up with a fun way to do that. Mho's Resistance is an app for the iPad or iPhone that helps you learn to decode and encode resistor color bands through a fun game which will appeal to kids.
Mho is the cute resistor character who appears in the Adafruit Circuit Playground series of videos for teaching electronics to young kids (we're eagerly awaiting the next installment!)
For beginners there's a helpful tutorial which explains what a resistor is. You then learn about the colors and positions and what they mean and get to practice before you start to play the game which has various modes.
The game is nicely put together and a brilliant way for kids to actually to learn something useful while playing a game. (It's actually a good way to make sure kids really understand place-value and big numbers in maths too.)
The app costs $0.99 but you also get a code that gives you $0.99 off an order from the Adafruit store where you can buy all sorts of useful electronics goodies or get a plush Mho.
Buy: Mho's Resistance on iTunes