Topics: Tips and tricks to get cheap flexible flights?
• If you're planning to get married in a Portland park in 2018, today's the day to jump into the Portland Parks & Recreation's wedding permit lottery. Starting at 8 a.m., people can submit applications for wedding permits online at http://www.portlandparks.org, or by calling 503-823-2525. Cost: $110 nonrefundable fee. Lottery drawing is Friday, Dec. 15. http://www.portlandoregeon.gov/parks/weddings
• See Outside the Frame's new documentary "Leaving Home," and new films by Portland's homeless youth, 6:30 p.m., The Armory, 128 N.W. 11th Ave. http://www.facebook.com/OTFPDX
• Learn how animals adapt to their environments at Science on Tap, 7 p.m., Alberta Rose Theatre, 3000 N.E. Alberta St. Cost: $15 general; $8 with student ID. http://www.viaproductions.org/