STANDING ROOM ONLY. These three words stamped in bold type across a theater poster or advertisement create an aura of unavailability around a production. However, as blockbusters become more frequent -- and the ticket prices increase -- the aura turns to pragmatism, and more patrons resort to the cheaper SRO tickets as a practical way to see a "hot" production.

The economy has democratized the SRO line. A few years ago, college students clad in jeans and equipped with textbooks dominated the lines. Not so anymore. At a recent Kennedy Center sell-out, senior citizens and middle-aged, middle-class types were waiting with the blue jeans crowd. People who don't want to bother with the time and inconvenience of SRO have developed some pocketbook-saving patience.

Ticketplace (the half-price day-of-the-show sales booth on F Street) is not always helpful in the search for bargains on popular shows such as "Ghosts," "Dining Room" or "Napoleon." If a show is selling well at regular price, the theater doesn't make any tickets available to Ticketplace. Why should they? Discount tickets are only needed when the house is not selling out. And, if 80 or 90 percent of the seats are sold, the theater will probably sell out those remaining empty seats before any SROs go on sale. That is why the ticket window doesn't usually open on the day of performance until two hours before curtain time. But if a show is sold out, as Francis Ford Coppola's "Napoleon" was, SRO tickets may be sold prior to the two hours before show time.

The Kennedy Center SRO scenario:

1. Ticket-seekers must line up in the hallway outside the box office and stay lined up because

2. You cannot hold a place for a person in the line.

3. Since only 40 SRO tickets are sold, persons at the head of the line get priority on all sales -- including any return tickets that a purchaser is attempting to resell, however

4. No scalping is allowed, and a Kennedy Center person supervises the sale of the tickets being sold by a previous purchaser, literally standing between the two parties and as a negotiator. The price may not go over the Kennedy Center's -- but it can be lower.

5. If you leave the line to go to buy coffee, you lose your place and must go to the back of the line; no one can save your space.

6. You can leave the line to go to the restroom; however, the usher must be informed in advance of your reason for leaving, and you cannot stay away for longer than five minutes.

7. Prices for SRO tickets are usually $5; however, SRO tickets sold for $9.00 during Francis Ford Coppola's "Napoleon."

8. The purchaser can only buy one ticket.

9. There are no refunds or exchanges on either SRO or regular-priced tickets.

These rules are only good in Washington. Since New York has been a theater capital longer, New York state law sets the terms for SRO ticket policy there. Most Broadway and off-Broadway theaters issue slips of paper with numbers to SRO ticket-seekers, who line up outside the theater. Scalpers are only forbidden inside the theater. "They can scalp if they are outside the theater and they don't let us see or hear them," says one box-office saleswoman. Since SRO ticket-seekers are outside the theater, the restroom policy is up to them.

Thus, the rules for the uninitiated. If they seem too complicated, buy a season's subscription. If the subscribers fill up the house, they might push the SRO allotment back up to 50.