In 1996, a group of teenagers were camping in the Curlew Mountains. As they were erecting tents, they became aware of creatures nearby, which they took for animals. Then they suddenly found themselves the target of stones being thrown at them by little beings, knee high to them. They fled.
Although my source for this is a book in Irish UFOs*, there is no direct mention of a UFO being involved, only it does mention lights having been seen for years in the area. There also seems to have been an element of missing time. However, stone throwing seems a bit primitive for alien activity.
*The book in question is Conspiracy of Silence by Dermot Butler and Carl Nally.