ART FAIR: Multiplied Art Fair begins today at Christie's South Kensington, with a focus on contemporary art. It's the fashionably late arrival at the party of art fairs sweeping London this week. Runs till 15 October. Free, just turn up, 9am-7pm
GIVE BLOOD: Three locations collecting blood today: City of London Brewers Hall 9.45-11.30am and 1-4pm; Southwark Street Hop Exchange 11am-1.30pm and 3-5.30pm; Stoll community hall in Fulham 2-4.30pm and 5.30-8pm
BANG!: Photographers' Gallery has a bit of an odd one starting today. Existential Photography displays photos of people shooting guns at the camera. At the end of the show, you get to fire a gun at your own camera. Their website puts it much more artfully. £5, 10am-6pm
CHEESE, AND SOME WINE: There's a festival for everything these days (no, there really is...see below). The Southbank Centre gets first prize for gastronomes, though, with this weekend-long Cheese and Wine festival beginning today. Plenty of tastings and opportunities to buy. Free (mostly), just turn up, 11am-8pm
IMPRESSIVE ART: Although the discerning art lover is more than spoilt for choice with fairs at the moment, tip for the week comes from Laura Porter of @AboutLondon, who recommends Sotherby's pre-auction exhibition of contemporary art: "Banksy to Picasso, Andy Warhol to Bridget Riley — seriously, every big name contemporary artist under the sun has a piece in this auction! Eric Clapton is selling a Gerhard Richter for £12million to give you an idea of the value of these artworks." Free, just turn up, 9am-12 noon
MEMORY MARATHON: The Serpentine Gallery's weekend long Memory Marathon begins today, with a packed programme of talks, performance and music all themed around memory. Tonight, you can see/listen to a five-hour classical Arabian music extravaganza. £8, 6-11pm
CULTURES: The Native Spirit Festival (PDF) — highlighting indigenous cultures from around the world — begins this evening at the School of Oriental and African Studies (SOAS) in Bloomsbury. The opening night includes poetry, film and Colombian food. Free, but donations appreciated, from 7pm
COMEDY: The first London Irish Comedy Festival starts tonight in the Camden Irish Centre. @LondonIrishComedy. £18, 8pm
FAIRY TALES: Something a little out of the ordinary at Rich Mix in Shoreditch tonight, with an evening of Serbian fairy tales performed with traditional folk music. £7 (advance), £10 (doors), 8pm
SINGLES: Tonight's biggest party for the unattached takes place at the London Fields Brewery, where Monty's invite you to come along with a mate and leave with a date. It's £12 for a pair of tickets (because you can't go alone, you must bring a hot single friend). From 8pm
SKATE: The Friday night marshalled street skate starts from Marble Arch and is open to anyone competent and confident on skates. Free, just turn up, 8pm
CLASSICAL: Ealing Autumn Festival begins today with a 'Celebrity Recital' featuring Julian Lloyd Webber and Pam Chowhan working their talented ways through eight classical pieces, including one by Julian's dad William Lloyd Webber. It's at Ealing Town Hall. £25, 8pm
80'S PARTY: The Lost Angel in Battersea is the venue for tonight's Midnight A Go-Go, a club night for anyone who misses the 1980s. £5, 10pm-2am
Random London Trivia Of The Day
There are five pubs in the Soho area called the Blue Posts. Look, we did a pub crawl round them once. Turns out that in Georgian times, sedan chairs (a kind of footman-carried taxi) were hired out at places marked by blue posts. Our cinquefoil of pubs were built near five such locations.
Sun, sun, sun...all morning and well into the afternoon. Then, just as we're all getting ready for the Friday night pints, BAM! Rain, rain, rain. It might just pick up for around 6pm, though.
Secretly Hidden Tip Of The Day
Don't waste money and time visiting expensive art fairs like Frieze. Simply develop a consummate talent for painting, or casting bronze, and make your own art.