But seriously, alteclansig, SO, and Old Dog are on the money. Nearly any day (sans Friday) is packed with both newbie and experienced players. Some are quite good and provide an excellent challenge. If you have transport out to Tempe, it's worth the drive.
Thursdays WILL have excellent players bringing their A-game, so be prepared for that. Saturdays are a mix and sometimes packed full of kiddos out for a birthday party. Sundays are usually relaxed and very mellow. The crowd varies greatly, so you might want to call ahead of time to see how it is. Fridays, as said before, can either be a complete wash or provide some very small, fast moving games with players that can't make it any other day.
Not sure if mentioning AA gets you a huge discount anymore, but it's worth a shot.