Not many places in Pittsburgh specialize in oysters but luckily Muddy Waters does and knocks it out of the park. Not to mention they have an excellent happy hour with oysters included. Then Tuesdays they do a late night happy hour from 9pm - 11pm. The bubbles are $10.00 off bottles and champagne are $20.00 off bottles. They also have boilermakers on special.
Muddy Waters is my go-to since to me you can't go wrong with oysters and bubbles.
Also, it has to be mentioned that the staff is lovely, Adam has really hired excellent people.