Was it Zathura ? Here is the trailer.
Extract of the wikipedia page (emphasis mine):
Brothers Walter and Danny don't seem to get along with each other, or with their older teen-aged sister, Lisa. While staying at their divorced father's home while he is away at work and Lisa is asleep, the boys discover an old clockwork-driven space-themed board game called "Zathura" in the basement. The two begin to play the game, the goal to be the first to reach the final space named Zathura. During each turn, the game provides a card with instructions, but the two quickly realize that the cards affect reality, starting with a meteor shower. They soon discover that the house is floating on a small rock alongside Saturn.
The two little brothers, as seen in the trailer, can easily be remembered as being about eight or nine-year-old.
I think it matches every point of the description, except maybe the elevator part, but as Gnemlock puts it in the comments, there is a scene with a dumbwaiter which could fit.
Little known fact: Zathura (the book) is the sequel to Jumanji (the book).