We leave September with a bang of family fun, from celebrating a great new park and taking the Littles to tea, to pumpkin bowling and sea creature crafting.  If that’s not enough action, pick one of several fall-themed festivals happening this weekend, including the 50th Annual St. Demetrious Greek Festival (always a good time with dancing and delicious treats), the Fisherman’s Fall Festival and FidoFest at University Village.

Seattle

Lake Union Park Grand Opening
It’s a big day in SLU, with the much-anticipated opening of the waterfront park. Gotta hit the kid zone, for face painting, spin art, puppet shows and a performance by Bubble Man. Sat., 7 a.m. to 7 p.m., South Lake Union, Free. Event details.

Under The Sea Tea at Seattle Aquarium
Your mini mermaids and mermen  get to have high tea, aquarium-style, with treats, crafts and a super-cool dive show. (The price includes admission, so you can make a whole day of it.)  Sun., 1:30 to 3 p.m.,  Seattle, $20 for children, $30 for adults, reservations required. Event details.

Fremont Oktoberfest
It’s obvious why the adults love this annual festival, but the kiddos will be happy too, with great activities like pumpkin bowling, lifesize mural drawing, zucchini decorating and pumpkin carving. Plus plenty of (root)beer.  Fri. to Sun., various times, Fremont, $15 to $30. Event details.

Eastside

Worldwide Day of Play on Mercer Island
Celebrate the 2010 Nickelodeon Day of Play Saturday by turning off the tube and heading to Mercerdale Park for gunny sack races, tug of war, bounce houses and other entertainment.  Sat., 1 to 4 p.m., Mercer Island, Free. Event details.

Fall Harvest Festival at Remlinger Farms
It’s kick-off weekend for Remlinger Farm’s popular seasonal fete that goes on through Halloween.  Get your autumn fix with the u-pick pumpkin patch, the corn maze and the family fun park.  Sat.-Sun., 10 a.m. to 6 p.m. through October 31, Carnation, $15.25. Event details.

Get Crafty Saturdays at Bellevue Arts Museum The exemplar Creatures from the Deep exhibit will inspire curious, little minds to make sea creatures out of everyday materials. Sat., 1 to 3 p.m., Bellevue, $2 or free with museum admission. Event details.

—Kavita Varma-White