There's actually a really good app version of it on the play store that works for single/multiplayer. You can put it on a tablet and have everyone sit around the tablet or pass it around. In some ways it's less complex and in other ways it's more complex. The whole game revolves around planning out moves that you can work around and trying to sabotage the other players when you run out of people to populate the cities/fields/roads. You get more points the bigger the city/longer the road/more complete cities connected to the fields. You can set yourself up to weasel in on other players areas and make them basically split their points with you. It's a lot deeper game than it looks on the surface. All that being said, you can't go wrong with Catan either.