GIVE BLOOD: In the City? Donate some red gold at the Barbican YMCA. Free, just turn up, 9.30-11am and 12.15-4.15pm
ART: London gets a new gallery today. Atomica in Sclater Street, Shoreditch will start out as a pop-up, showing under-appreciated contemporary art, becoming permanent sometime in 2013. Free, just turn up, 11am-7pm
CHRISTMAS FAYRE: University of the Arts London hosts a Christmas Fayre on the parade ground next to Tate Britain. Turn up for all kinds of Christmas treats, and a chance to talk to university students about the work they're engaged in. Free, just turn up, noon-8.30pm
ROMANTIC CHEMISTRY: This apparent contradiction was a reality in the early 19th Century, when figures like Humphry Davy was as happy writing poetry as discovering chemical elements. A new exhibition at the Royal Society, running until 14 June 2013, explores this fascinating era. Free, just turn up, Tue (2-4pm) or Thur (10am-noon).
SHERLOCK: Meet Mark Gatiss and Steven Moffatt, creators of BBC's Sherlock (and many other wonders besides) at Waterstones Gower Street. It's first-come-first-served, so get there early if you want to lead the queue. Free, just turn up, 12.15pm
DORIS DAY: BFI Southbank launches a season of Doris Day films this evening, intent on "restoring the reputation" of the actress often dismissed by film snobs. Catch an introduction to the series tonight at the venue. £5, prebook, 6.20pm
FILM: Catch a screening of the 1931 version of Dr Jeckyll and Mr Hyde at UCL’s JZ Young theatre, followed by a wine-enhanced tour of the Grant Museum. Free, just turn up, 6.30pm
FREE SPEECH: Index on Censorship launches the latest issue of its magazine with a very timely discussion about free speech online at the Free Word Centre. Richard Allan from Facebook, Gus Hosein from Privacy International and Kirsty Hughes of Index on Censorship are the speakers, and there’s drinks and sushi for everyone. Free, prebook, 6.30pm
ONLINE PHOTOGRAPHY: The Photographers’ Gallery holds a talk that goes by the alluring name of All Your Cat Memes Are Belong To Us, examining the use of images online. £7, prebook, 7pm
GIGS: Ben Folds Five, all three of them, play Brixton Academy. £42.18, prebook, 7pm
CLOTHES: We're not sure if it counts as a pun, a spoonerism or both, but Get Rich Or Tie-Dying at Shoreditch Book Club is certainly among the more painfully named events we've seen. Learn how to tie-dye clothing, for gifts or for that authentic Camden Market look. £12, just turnup, 7.30pm
Random London Fact of the Day
BBC Television Centre in White City was designed in the late 1950s by Graham Dawbarn. The story goes that, while playing with ideas to fill the triangular plot, he inked in a giant question mark. The typographic doodle turned out to be a fitting design solution, and the studios were built to that shape. When the newsroom was added in the 1990s, it was specifically built into a drum shape to form the dot at the bottom of the question mark. To find out more, go on a tour of the centre.
In a switcheroo of Monday, the day will start bright and sunny and slowly gloom over. The wind will mostly be blowing into your left ear, assuming you're using the same frame of reference as us. BBC Weather has a more helpful report.
Secret Hidden False Rumour Of The Day
In contrast to the BBC's question-mark studios (see above), ITV's main headquarters are shaped like a giant yawn.