(1) The PCs are in a rocky area, a day or two after torrential rains cut large gashes in the thin soil. If one is observant enough, one may notice that something is buried under a thin layer of mud--something with suspiciously straight lines and sharp corners.
If the party decides to excavate, they will find a flat stone slab some 10' on a side, inscribed with strange glyphs, some magic, others mundane yet exotic; whatever its nature, its extreme age is obvious. If the PCs put their minds and spells to it, they will realize that it's some sort of AD&D "transporter pad" (for those Trek fans out there).
Can they figure out how to operate the device? Does it still work normally, or is it damaged? Where will it take them?
(2) The PCs' camp is raided during the night; only food is missing, no one is harmed, and a single pair of ogre footprints are found. The PCs decide to track the ogre (to investigate, not to kill, at least for the moment).
If the PCs stay their weapons long enough, they will discover the ogre's lair--filled with cages holding sick animals, both natural and fantastic. If the PCs play their cards right, they can gain the ogre's trust, help him with his charges--and gain a wealth of information and perhaps some treasure from the good-hearted but simple-minded ogre.