Super-slimy sloppy (human) slug races, advanced degrees in slugology and other whimsical wackiness are the order of the day during Slug Fest, Northwest Trek’s tribute to the misunderstood native banana slug. Grown-up gardeners can even get tips on ways to discourage the nasty non-native European slugs from munching the marigolds. Free with park admission. Hours are 9:30 a.m. to 5 p.m. with trams running hourly.