My husband did this a couple of weekends ago and managed to get tickets. Assuming it hasn't changed since then, they take names an hour before curtain, then you're free to leave until closer to curtain (not sure of the exact timing but I was shocked they didn't make you stand in line the entire time). He arrived about 40 minutes before they took names and ended up getting the last 2 of 4 available tickets. They're nice in that they let you wait in the lobby, which I was also surprised by. He ended up getting house seats for $47 (or somewhere around there), which was great. Just note that there's no guarantee you'll be sitting with your +1 if you manage to get tickets.