It's not LEGO-related, but for a constructive and [in my opinion] very fun computer game, check out the popular Minecraft. The block-built worlds are essentially infinite. There is a "creative" mode where you have an unlimited palette of materials, and a "survival" mode (with optional monsters) where you must collect the materials needed to build the tools needed to collect different materials to build better tools and buildings… and so on.
I received a LEGO board game, Minotaur, as a gift. Although it is not particularly building-oriented, it has proved fun as a party game and is more amenable to modification than the video games, since the board is actually built with LEGO pieces. The goal is to move your pawns to the center of the board; certain rolls of the die instead allow you to move the minotaur or pieces of the "labyrinth" itself, blocking the way for your competitors.
I received a LEGO board game, Minotaur, as a gift. Although it is not particularly building-oriented, it has proved fun as a party game and is more amenable to modification than the video games, since the board is actually built with LEGO pieces. The goal is to move your pawns to the center of the board; certain rolls of the die instead allow you to move the minotaur or pieces of the "labyrinth" itself, blocking the way for your competitors.