I do not know where they came from but but having shot quite a few I have seen that some are better than others - more smoke than sparkle.
Also just a heads up that some venues will not allow them.
If you put a few to the side then you can also have some fun with them - here are a few of the usual ideas.
Top tip -The person doing the letter has to do it in reverse from their perspective. SO give the "O" the job of the drunkest volunteer and the "E" the job of the sober one