The Dupont Circle Citizens Association is hosting its annual house tour this Sunday as 11 historic houses pull back the curtains and open their doors for the public to have a look-see inside. Many of the houses that surround Dupont Circle were designed by architects trained in Paris at the Ecole des Beaux Arts. This year's house tour ranges from S Street NW on the north side of Dupont Circle to Massachusetts Avenue on the south side, and from Connecticut Avenue to 23rd Street NW. Tea will be served at the Friends Meeting House, 2111 Florida Avenue NW, between 2 and 5. Tickets are $9 in advance, $10 on Sunday. Hours are 1 to 5; call 387-5312 for details and ticket information. * Homeowners in Smithfield, Virginia, are welcoming the public in, too, Saturday from 10 to 5, and Sunday 1 to 5. You can wander through homes dating back to 1750 as well as take in Smithfield's other historic sites. Brunswick stew, ham rolls and homemade pies will be on sale on the courthouse lawn if you get hungry. Tickets, available at each house, are $6 for the complete tour. From D.C., take I-95 south to Richmond, exit at Hopewell north and continue to Route 10 south into Smithfield. Call 703/357-7131.