A restaurant will never go too far wrong with enormous servings at lower-than-normal prices. That has always been the hallmark of R&O's food--but it's good, too. Now that nearby West End Park is bereft of its restaurants, R&O and its neighbors in Bucktown are even more important to the casual dining scene, even without a view of the nearby lake.
R&O (it stands for Roland and Ora, the founders) began in 1980 as a tiny cafe in the back of an ancient Bucktown grocery store. It served then most of what it does now: poor boys, pizza, and seafood. It drew crowds so large that it since moved twice, each time to a bigger spot. It still remains full at all hours. In 2007, they opened a second location in Covington, but it never took off, and is now closed.
One enormous room with a high ceiling, the walls decorated with mounted fish and other standard lakefront touches. On the noisy side, largely because of the number of people who jam in. The service staff squeezes between the tables to deliver a rushed service that doesn't seem to upset the hungry customers.
Show up later in the evening rather than the busy early hours. Have one person with a cellphone wait in the restaurant while the others with you (one of whom also has a phone) hangs on the levee across the street. Avoid Fridays.