Halloween can be educational. In addition to teaching children about math (candy nutrition labels), geography (mapping out a trick-or-treat route), history (Halloween folklore), and extortion ("Trick or treat!"), it's also possible to learn about physics. The way to do that is with a Halloween bubble light.
I don't know why bubble lights went out of fashion, but showing a child that something that is boiling can still safe to touch is an opportunity to learn about the phases of matter, the elements, boiling points, and all kinds of happy physics and chemistry things.
Also, it's never too early to put up Halloween decorations — if they're educational.