Planet of the Nose Pickers — Gordon Korman

When Devin discovered that Stan, the foreign exchange student his family was hosting, actually came from another planet, rather than another state, it took a little work, but he managed to deal with it. And when he learned that his teacher was a UFO nut who was hot on Stan's tail, well, he found ways to protect his friend; but the trouble was only beginning. For Stan is actually a travel agent from the planet Pan, trying to get Earth selected as Pan's next premier vacation destination. Unfortunately, he is in competition with Pan's foremost agent, Shkprnys (who visited our planet under the name Shakespeare a few centuries ago), who is promoting Mercury as the destination of choice. When Shkprnys cheats, and gets Mercury selected, it spells death for the human race, as the planet Earth will be towed out to the outer rim of the solar system, to provide mercury with a better view of Saturn's rings ... and freezing our entire planet. To save the Earth, Devin and Stan must accompany the Smarty-Pants back to Pan, to argue their case with the planet's supreme leader, the Grand Pant. But with the bizarre social structure of Pan, it may be impossible to even get to see the Grand Pant, much less convince him to save the Earth. Can our reluctant heroes save the day?