The mid-century Christmas room at the Geffrye. Courtesy the Geffrye Museum.

There are simply too many things happening in London over Christmas 2005 to mention them all, but the 24 Hour Museum has picked out a few festive treats and general exhibitions that will make venturing out into the cold worthwhile.

Christmas Past is a perennial favourite at London Museums. Go to the Geffrye Museum to see how they did it in decades gone by. 400 Years of Seasonal Traditions in English Homes is running until January 8 2006, with the museum’s 12 period rooms decked out in keeping. The meanings of customs such as kissing under the mistletoe and decorating the tree are also explored.

It's Christmas medieval style at the Tower of London. Courtesy Historic Royal Palaces.

The Tower of London is going back even further, to the 13th century, to demonstrate Christmas medieval style. From December 27 to 31, 2005, you can join the court of King John Edward I in celebrating Christmas 1284. Expect fools, musicians, entertainers and guests with shiny goblets brimming with wine, and a lavish feast with all the raucous banter of the age.

The Victorian Christmas of 1850 will probably feature more familiar fayre. That’s the era you’ll step in to at the Church Farmhouse Museum, Hendon, until January 5 2006. The display reveals that so much of what we think of as the traditional British Christmas - Christmas trees, Christmas cards, crackers, turkey for dinner, even Father Christmas and the giving of presents on 25 December - was either invented or introduced here from other countries by the Victorians.

Look behind you! It's panto time at the Theatre Museum. Courtesy the Theatre Museum.

What would the season be without that other great British tradition, panto? The Theatre Museum is celebrating pantomime with workshops running daily from December 17 to January 8, (bar December 25, 26). At 2pm and 3.30pm, you can be transformed into a pantomime animal, or arrive at 12.30 to learn about panto acting methods. On the hour, throughout the day, you can find out about the outlandish make-up needed to be a proper Widow Twanky.

Check with the Theatre Museum for various other activities such as storytelling. On December 17, take a guided walk around Drury Lane and the Strand at 2.30pm, learning about the Dickensian Christmas (£5/£4, book on 020 7943 4750).

The White Witch from the Chronicles of Narnia. Courtesy IWM.

Moving from stage to screen – The Chronicles of Narnia: The Lion, the Witch and the Wardrobe is bound to be the Christmas blockbuster at cinemas. The book, by CS Lewis, was inspired by stories he told to evacuees during World War Two, hence the Imperial War Museum is taking up the theme between December 17 – 22 and 27- 30, 2005.

Visitors can walk through the wardrobe to the enchanted land of Narnia, meet a wartime evacuee and the White Witch and discover a different world. The adventures start at 12pm, 1pm, 2pm and 3pm.

Basket Forest, 2002. Photo by Terry Rushel, courtesy Kew.

It’s the last chance to see the magical glass sculptures of Chihuly at Kew. The Garden of Glass will be open until January 15, 2006.

If you still want to enter another world before Christmas is out, the Science Museum might have just the thing. The Science of Aliens explores our wildest imaginings and allows visitors to write their own message to an alien (with possibly more effect than writing to Santa). The exhibition runs until late February, 2006.

Finally, for a really different place to go, on Saturdays December 17, 24 and 31 2005 the Brunel Museum in Rotherhithe is giving guided journeys of the Thames Tunnel by tube train. The tunnel will be floodlit so visitors may see its columns, recesses and architectural features as they pass by. Tours commence at 1pm, 2pm, 3pm and 4pm - phone the museum on 0207 231 3840 for more details.