How to make yourself run a real fever?

3 Weeks more and I'll have to go camp.But i don't want to go. Is there any ways to make yourself to run a real fever?I can't afford to take the risk of feigning fake symtoms as they would take me to the doctor.And I want the fever to last for 2 days or more.Please do not give me answers that are beyond my power.-Lick ****,lick toilet,eating something disgusting,etc.