Common question is how to find girls for one night stand easiest, Answer: locally is simplest way to get girl for one night stand.
Reasons are obvious: It is free, it is near you, and it is best way to get laid fast, just going to local bar, club or some other popular place.
Check also what wikipedia says about one night stands.
Depends on country and culture, somewhere people (both men and women) are very active in this kind of getting intimate with opposite (or same) gender so one night stands are very common.
You can even visit less popular places; it depends on how you see your chances.