Can't think of the name off the top of my head...but it's just trains. You have to plan train routes across the U.S. (and part of Canada), and try to block others from accomplishing their routes. It's pretty fun.
Clue was always a favorite of mine...don't know why I haven't bought that one for the kids, yet...
Monopoly, though it can get pretty heated in my household
Samurai Swords is a fun card game; my kids love it.
And, it's not a board game, but any of the Just Dance games for the Wii can be fun for the whole family, and you get some exercise, too.