ever since i was younger, i've spent countless hours on the NBA 2K MyLeague game mode. rebuilding and retooling teams has always been fun to me, even on Madden.
i haven't been buying those titles recently so it's convenient to have access to the same type of simulation game, through the convenience of my web browser, without being restricted by the gaming consoles at my disposal.
you can even load custom rosters that other people have created, to make the experience more NBA-accurate.
there's also a football GM edition of the game, which i've used to do NFL rebuilds.