This one is easy for the Strip: the Boardwalk. No one thinks to go there because it isn't exactly first class, but they set up a little lounge like area for the weekends with a bunch of TVs close up. The betting numbers are the same as the MGG Mirage group, but unlike the rest of its properties, you can actually get a seat on Sunday. Parking isn't tough either. You can ask 100 people and you probably will never hear this advice, which in itself makes it valuable.
Off Strip the best places are usually dedicated sports bars if you have a particular team. Go to
www.lvrj.com and there is a listing for all the bars that will only show the given team's games. If you are more concerned about action on all the games, Barleys is a good choice, but a bit crowded. Also you might have to sit at the bar so you will be paying out some cash for your drinks, but still convenient spot to catch all the games.