I'm assuming this thread is talking about browser games and have to go with Clicker Heroes as one of my favorite games to play right now. Once you start, say goodbye to your life for a few days because you'll be addicted. Its strange because all you want is to do more dps and collect more gold. What I particularly like about it is you don't have to actively play the game once you get relics and artifacts going at a decent pace. Been playing my current save for about a month and its become something I check on a daily basis.