'Mexican Sally' formally known as Salvia divinorum, is a plant found in mexico, which is psychoactive. The plant creates "visions" and other hallucinatory experiences. The drug is extracted from the leaves, and smoked via a water-bong, however smoking (roll-up) or digesting the leaf, will not induce hallucinations, and will only create mild 'highs' (the taste is also potent).
It is legal in many countries whereas it can be grown and used for recreational use, however countries including Australia, Belgium, Canada, Denmark, Estonia, Finland, Italy, Japan, United States, Russia, Spain, and Sweden have imposed 'some' regulation towards the drug.
A nice lady. She can often be found greeting individuals entering your local Wal-Mart. She is either Mexican or some ethnicity that isn't white and looks somewhat Latino. She's an all around magnificent person that deserves a pay raise. However, if you talk to her, she won't be able to understand you as she can't speak English. She is also most likely not named Sally.
Damn, look at that Mexican Sally. She's greeting everybody going into Wal-mart. Too bad she can't understand us.