What are "Supernatural mental abilities" in relation to Buddhism?

In this question [How to help non-Buddhists understand a young person's desire to be ordained as a monk?](https://buddhism.stackexchange.com/questions/137/how-to-help-non-buddhists-understand-a-young-persons-desire-to-be-ordained-as-a) , one of the "selling points" listed was: >5) Supernatural mental abilities (astral travel, reading minds, remembering past lives, etc.) Could someone explain this is more detail? I had thought this was more of a pop culture point rather than what seems to be a core concept. Do such "abilities" actually exist, and if so what is their implication in the practice of Buddhism or proceeding in one's daily life? Do monks or others actively practice them?