In case you missed Google's April Fool's Day fun, don't worry. They'll get you again--they always do.

This year's hoax--Project Virgle--offered space buffs the chance to join the first human colony on Mars (2014) and featured an online application, a "test of pioneering potential," and a map of the planned landing site along with convincing burble about the red planet's "mineral goodies that . . . will form a solid foundation for agricultural self-sufficiency and the building of an advanced industrial society."

YouTube messages from Google founders (and pranksters) Sergei and Larry along with Richard Branson of Virgin (hence, Virgle) capped the hoax.

Hoaxes and urban legends are not only hilarious--they're great thinking opportunities for the whole family. You can help to hoax-proof your kids with the SNIFF test. Before you commit to believing, run through this checklist:

Sounds too good (dumb, sweet, exciting, scary) to be true? It probably is.

Never heard anything like it? Then wonder why. The unique capacity of Virgle to establish a Mars colony by 2014 is a good example!

Images look enhanced? Well, they might be. Or totally fake.

Feeling titillated, weird, or otherwise manipulated? Watch out!

Finding no corroborating evidence? Then something stinks.

Now that you're a SNIFF expert, why not talk about some famous hoaxes and urban legends with your kids? Encourage them to ask questions and respond to ideas by hoaxers and debunkers alike. Which ideas sound most reasonable to them? Why?

Start by looking on All About, Snopes, and Bad Astronony for material to discuss. You'll be surprised at the number of science and geography connections. Example: The Great Wall of China is not only NOT visible from the moon, it isn't even visible from low orbit (about 180 miles up) because it blends so well in with the surrounding topography! If you homeschool, you could do a whole unit on urban legends as a genre. Teens may enjoy discussing the psychology of urban legends. Why are people are so ready to believe, anyway?

Maybe you can still remember the shivery feeling you had upon hearing your first urban legend. Neat feeling, I know. But it sure doesn't beat pouncing on an e-mail and thinking, "Naaah."