This week, I’m most excited to point you to Drawings & Object by Architects, closing Saturday, October 10 at the Edward Cella Art and Architecture gallery in Los Angeles. The show is a stunning collection of original drawings by some of the most notable architects of the previous century: Richard Neutra, Frank Gehry, and Frank Lloyd Wright. I wasn’t able to see it myself and if you’re not able to get to it either, you’re still in luck because there are nearly 70 images from the exhibition posted on the gallery’s website, which you can view here.

Also closing, on Monday, October 12, is Mannahatta/Manhattan: A Natural History of New York City at the Museum of the City of New York. This exhibition, presented in collaboration with the Wildlife Conservation Society, lets you imagine what Manhattan was before we covered it with concrete and moved in 1.5 million residents—not to mention the millions that make their way into the borough each day. Again, for those of us who can’t make it to the show before it closes, you can see more online at The Mannahatta Project website.

Happening now is DesignPhiladelphia 2009. The fifth-annual weeklong event kicked off Wednesday, October 7, runs through Tuesday, October 13, and features lectures, workshops, studios, tours, and exhibitions throughout the city. Weekend highlights include: an exhibition of bike parking proposals on view at the Piazza at Schmidts at 1040 N. American Street, the Gimme Shelter show at the Schuylkill Center for Environmental Education, and a guided tour Saturday, October 10, presented by the Preservation Alliance for Great Philadelphia and DOCOMOMO North America showcasing modern buildings in Philadelphia and the efforts being made to keep them around. For more, visit DesignPhiladelphia.org.

Last but not least, the new exhibit Slash: Paper Under Knife opened this week at the Museum of Art and Design in New York City. On display until April 4, 2010, this exhibit is the third in MAD’s “Materials and Process” series and includes works in paper by Olafur Eliasson (who laser-cut geometric patterns into a hand-bound book), Noriko Ambe (who created the topography of the world in papers filled in a metal cabinet), and others. View them online at MAD’s website.

Know of a great modern art, architecture, or design exhibition or event that should be added to our online calendar? Submit your suggestion here.