This year’s sophomore class never saw the inside of the place. The Class of 1897, the first to see it ever, would find it at once familiar and strange if they were around today.

And those who remember what it looked like before it closed for a four-year reconstruction are in for a very pleasant surprise.

Houston Hall, the nation’s first student union and the centerpiece of the Perelman Quadrangle, is once again open for business, and starting today, the University will celebrate with a week-long grand opening.

With the reopening, the Perelman Quadrangle project is substantially complete, and events throughout the week, including the “No Place Like Penn” festival Sept. 14 to 17, will take advantage of all of its facilities and spaces. Concerts, receptions, talks, food and drink are all on the menu for the Perelman Quad grand opening.

Here are highlights of the celebration; “No Place Like Penn” events, marked with stars, are free for PennCard holders unless otherwise noted. A complete list of “No Place Like Penn” events can be found at www.upenn.edu/perelmanquad/nplp on the Web.

Thursday, Sept. 14

TIME CAPSULE: A “Millennium Time Capsule” chronicling student life at Penn in the year 2000 will be placed in Houston Hall. 4 to 4:30 p.m. in the Houston Hall main lobby, 3417 Spruce St.

BEAUX ARTS TEA: The Faculty Senate’s year-long series of performances, lectures, exhibits and tours kicks off with a formal faculty tea. 3 to 5:30 p.m. in Reading Room, Houston Hall.

GRAD STUDENT GALA: All new and continuing graduate students are welcome at this party celebrating the Perelman Quad opening. 5 to 9 p.m. in Hall of Flags, Houston Hall.

Y-100 COLLEGE TOUR: The rock-hits radio station will be handing out freebies at 6:30 p.m. on Penn Commons, between Houston and College Halls. *

SAY IT!: That audience-participation fave, “The Rocky Horror Picture Show,” will be shown under the stars. 8 p.m. on Penn Commons; props provided. Rain location: Hall of Flags, Houston Hall.

Friday, Sept. 15

ACTIVITIES DAY: Check out all the student clubs and organizations on campus. Noon to 4 p.m. along the Perelman Quad gateway off Locust Walk east of 36th St. *

Saturday, Sept. 16

COFFEE’S ON US: The vice provost for university life and the Tangible Change Committee invite you to enjoy free coffee, newspapers and scones with your PennCard. The first 500 students will also receive a free travel mug good for 25 cents off coffee all year in Houston Market. 11 a.m. to 2 p.m. in the Houston Hall reading room. *

SEE THE HISTORY: A special exhibit celebrates the history and transformation of America’s oldest student union. Opening at 1 p.m. in the Fox Student Art Gallery, Logan Hall, 249 S. 36th St. *

SEE, HEAR AND TASTE: Enjoy an afternoon of activities, arts and crafts, and performances by The Ally, Mask and Wig, and the Jazzyfatnastees. 2 p.m. on Penn Commons; Mask & Wig performance at 3 p.m. and Jazzyfatnastees at 4 p.m. in Houston Hall Auditorium. *

THANKS, DONORS: Those who put up the money to make Perelman Quad possible will be honored with a reception, tours, dinner and a ceremonial ribbon-cutting. 5 to 8:30 p.m. throughout Perelman Quad.

DANCE PARTY: DJ Cocoa Chanelle of radio station “Hot 97” spins the jams tonight. 10 p.m. to 2 a.m. in the Hall of Flags; tickets available at the door. *

Tuesday, Sept. 19

STAFF OPEN HOUSE: Ben Franklin will be on hand to welcome Penn staff to tour the renovated Perelman Quad and enjoy entertainment, refreshments, giveaways and raffle prizes. Noon to 2 p.m. throughout Perelman Quad.

Wednesday, Sept. 20

MEET YOU THERE: Event and meeting planners on and off campus are invited to take a peek at Perelman Quad. 6 to 8 p.m. throughout Perelman Quad.

Thursday, Sept. 21

IRRATIONAL EXUBERANCE?: Jeremy Siegel, the Russell E. Palmer Professor of Finance, will try to answer the question “Are Stocks Overvalued?” 4 p.m. in Room 17, Logan Hall; reception follows in the Hall of Flags, Houston Hall. Tickets: Danielle Kradin, 215-898-7227.