Make it a good one.

CLIMB
The Treehouse Gallery
What: Last chance to see the outdoor installation playing host to craft workshops, talks, exhibitions and more.
Why: Tree’s company.
When: Thurs., 10 a.m.-4 p.m.; Fri.-Sun., 10 a.m.-8 p.m.
Where: Boating Lake, Regent’s Park (Hanover Gate entrance), NW1.

WATCH
Portobello Film Festival
What: Free cutting-edge cinema features British talent and more as part of unofficial indie film week.
Why: Roll with it.
When: Today-20 Sept.
Where: Various locations around W10 & W11. For details, go to portobellofilmfestival.com.

Short & Sweet Film Screenings
What: Weekly mini movies from established directors such as Simon Ellis and up-and-coming talent including Laurie Hill.
Why: For reel.
When: Mon., 6:30 p.m.
Where: Cafe 1001, 91 Brick Ln., E1 6QL (020 7247 9679).

ENTER
London Underground Moquette Design Competition
What: The winner’s new seating fabric will debut on the Piccadilly line in 2012 and everywhere else at a later date.
Why: Be a part of the underworld.
When: Entries must be submitted by 14 Sept., 5 p.m.
Where: Instructions and brief online at shop.tfl.gov.uk.

PARTY
Primrose Hill End-of-Summer Fete
What: Shop from stalls by locals like Graham & Green and Elias & Grace while kids enjoy crafts, food and face painting.
Why: Take to the streets.
When: Sun., noon-5 p.m.
Where: Regent’s Park Rd., NW1 8XN.