Are all LEGO Boardgames more or less for children, or are some of them suitable for grown-up, more expert players? (Everybody likes relaxing with a simple game, but are any of the games a bit more challenging?)
There are also a few examples of "Expert" rules that others have come up with, including our very own Joe Wreschnig's set on his dedicated site.
Both of these make the ruleset more complicated and can encourage more of a team play than the usual competitive play that my kids make it.
LEGO Creationary is another game where the modelling requirements make it a slightly less child friendly game than some of the others.