Play with the Laws of Motion. Kinetics! opens at the Children’s Museum of Denver on October 13, 2012. This new science and engineering exhibit will help kids discover the fundamentals of forces and motion in a life-sized marble run where balls cascade down ramps, roll along tracks, travel through tubes and fly over heads. Learn firsthand that for every action there is an equal and opposite reaction. Price is included with admission. Learn more at www.mychildsmuseum.org.

There are many great fall favorites this weekend!

Oct. 13: Punkin Chunkin involves using large slingshots, catapults, centrifuges, trebuchets and pneumatic air cannons to hurl pumpkins as far as possible. “Chunkers” from near and far make the trek to Aurora to compete in this official World Championship Punkin Chunkin Association event, a dynamite spectator sport. The associated festival offers the usual family activities, plus pumpkin carving demonstrations, a pumpkin patch, scarecrow making and more. Entry to the event and most shows is free; tickets for others are on sale at the gate. Parking costs $5 per vehicle. 10 a.m. to 5 p.m. Arapahoe County Fairgrounds, 25690 E. Quincy Ave., Aurora. Details at auroragov.org/ThingsToDo/Events/PunkinChunkinColorado/index.htm

Oct. 13: The annual Littleton Harvest Festival & Pumpkin Sale re-creates harvest time in 1860s Colorado (rain or shine, pioneers were tough!). The Littleton Museum’s 14-acre site houses 1860s and 1890s farms with costumed interpreters, the city’s original log schoolhouse, working blacksmith shop and ice house. Pumpkins planted on site are for sale. 10 a.m. to 3 p.m. 6028 S. Gallup St., Littleton; 303-795-3950 or littletongov.org/museum/events/details.asp?ID=4

Scarecrows on parade Oct. 13: Whimsical and cleverly designed scarecrows will be positioned throughout Arvada’s Olde Town for the family-friendly Festival of Scarecrows, where you can cast your vote for the best of the fest. Youngsters can join the Costumed Kids Parade led by Brewster the Giant Green Dinosaur. Each tiny ghost and goblin gets a goodie bag. Dedicated gardeners also enter their largest pumpkins for the nail-biting weigh-in at 1:30 p.m. Winners have exceeded a whopping 200 pounds. 10:30 a.m. to 2:30 p.m. Olde Town Square, Arvada; 720-898-7400 or arvada.org/arts-and-culture/festival-of-scarecrows/

National Wildlife Refuge Day. Oct. 13: There’s always something to see at the Rocky Mountain Arsenal National Wildlife Refuge, which many call the Denver area’s hometown wildlife habitat. Additional programs geared to families include nature-oriented arts and crafts, wildlife films on the big screen, hayrides, educational booths and visits by live birds of prey from HawkQuest and Rosie, the Butterfly Pavilion’s friendly tarantula. 10 a.m. to 3 p.m. 6550 Gateway Road, Commerce City; 303-289-0930 or fws.gov/rockymountainarsenal/

-Claire Walter, Laura Daily