The Coachella flu is something many suffer after a weekend in the desert. The partying mixed with lack of sleep and nasty desert dust can destroy your body, leaving you with flu like aches, lung issues, fever, etc.
There is a thread here somewhere with stories from sufferers. Be sure to hydrate, take emergen-c or something similar, saline for the nasal passages, bring a bandana or dust mask, and get some rest at night to lower your chances. Would suck to have an amazing vacation planned like that only to spend it wishing you were dead.
Haha I feel like Coachella is one of the least dusty festivals I have ever been to.