Ever since the opening of TICKETplace, the most frequent request has been for tickets for "Evita," usually framed in a pessimistic mode: "You don't have tickets for 'Evita,' do you?" The standard answer has been, "No, but there are a lot of other things going on," but last week, for the first time, a few hundred tickets for the hottest show in town went on sale for half price on the day of performance. So far, the only tickets have been for weekday performances, and National Theatre expects weekends to be sold out for quite a while, but there may even be weekend tickets (probably Sunday matinees) before "Evita" moves to Philadelphia in February. Other attractions currently or recently offered at TICKETplace include some concerts of the National Symphony, the Paul Taylor Dancers last week, "Banjo Dancing" and "A Lesson From Aloes" at the Arena Stage, "The Gospel According to Me" (Source), "Stage Door" (Hartke), the American Ballet Theatre (Opera House), "Romeo and Juliet" (Studio), "Hound of the Baskervilles" (Source), "Close Calls/Far Cries" (Pro Femina) -- practically everything except the Library of Congress, which adamantly refuses to reduce its 25-cent ticket price. The Washington Opera used TICKETplace for a couple of performances of "Macbeth" and may offer other tickets later in the season, but at the moment it is running to practically full houses.