Visit the Louis XV-style residence of the ambassador of Chile, the 1930s Romanian-style home of the ambassador of Romania and other embassies and renovated private homes Sunday from noon to 5 during the 20th annual Kalorama House and Embassy Tour in Washington's Kalorama and Embassy Row neighborhoods. Tickets cost $22 through Saturday, $25 on Sunday. Pick them up at the Woodrow Wilson House, the tour's sponsor, at 2340 S St. NW. Call 202-387-4062, Ext. 18.
A Revolutionary Opera
The Washington National Opera opens its 49th season with a new production of "Andrea Chenier," Umberto Giordano's tale of love and vengeance during the French Revolution, Saturday at 7 in the Kennedy Center Opera House. Mariusz Trelinski directs. Performances continue through Oct. 2. Tickets cost $45 to $290; call 202-295-2400 or 202-467-4600.
A Feline Festival
More than 400 domestic cats from dozens of breeds will compete and be displayed at the National Capital Cat Show, sponsored by the Cat Fanciers' Association, Saturday from 9:30 to 5 and Sunday from 9:30 to 4 at Dulles Expo Center, on Willard Road off Route 28 in Chantilly. Dealers will offer feline care and grooming supplies, toys and other goods, and rescue groups will arrange adoptions. Admission is $8, seniors and under 12 $5, a family of four $24. Call 703-421-7250 or 703-378-0910.
World-class equestrians and their speedy steeds compete across a course of obstacles, jumps and turns Saturday at the 17th annual Columbia Classic Grand Prix at Howard Community College, 10901 Little Patuxent Pkwy., Columbia. The gates open at 10; the junior/amateur Jumper Classic starts at 11:30 and the Grand Prix at 2. The event is a benefit for the college's scholarship foundation. Bleacher seats are $10, $5 for ages 12 and under; lawn space is $5, free for children. Call 410-772-4450.
The Kennedy Center's third annual Prelude Festival and its AmericArtes Festival: Espiritu de Puerto Rico continue through Sept. 26. Take 6, the Grammy-winning a cappella sextet, sings Saturday at 8 in the Concert Hall; tickets cost $20 to $40. Andanza, a Puerto Rican contemporary dance troupe, performs Wednesday and Thursday at 7:30 in the Terrace Theater; those tickets are $25. See story on Page 26. Call 202-467-4600.