“ A rumour of the knights of some powerful king that sleep until danger threatens the kingdom.
The truth is that they were rebels, trying to split the kingdom. Once captured they were put into an enchanted sleep, protected from age and harm, until their aims have been carried out by others in which case they will awaken.
There is a loophole in the spell in that trying to take one of their weapons will also awaken them.”
“ One of the camels in the caravan trips over a dark rock protruding from the sandy dunes. The poor animal has broken its leg and cannot continue. A cacaphony ensues as the animal suffers and the caravan train overseers complain passionately as they redistribute the animal's load across the caravan. (Let's just hope none of the PC's was riding this camel, shall we?)
As the camel is put out of its misery and the camel is skewered over a campfire - waste nothing! - someone takes a minute to inspect the root cause of all the trouble. To their surprise, the upturned rock is worked stone. Some frantic digging may excavate the bottom half of a gorgeously worked1 obelisk, and maybe even the small square forum below; but a more rigorous exploration of the surrounding dunes reveals a buried tomb doorway on each side of the forum.”
“ You find a patch of edible funghi. They taste well and all, no ill effects. UNLESS you consume some beverage, even 3 (three) days after eating it. Then you become really sick with pains, vomiting, all the fancy stuff. As a gift or good meal, it could be a cruel joke or to make sure the heroes spend their time focused on the mission. And the fine soup you had in the inn yesterday could have some in.
(Inspired through a real-world fungus. Was really used to cure alcoholism.)”