Towering above a busy intersection at one corner of the leafy Meadows in central Edinburgh, the former Edinburgh University Royal (Dick) School of Veterinary Studies has eschewed scientific research for more artistic preoccupations - not, occasionally, without their scientific bent - since it became Summerhall, a creative hub for the arts, 18 months ago.

The bustle of the outside world is reflected inside the 530-odd rooms that make up the maze-like complex, with no fewer than 128 exhibitions mounted since Summerhall was set up.

It's a staggering number, but if you are thinking more might mean less when it comes to quality, you would be wrong. Summerhall is building a reputation for critical and public successes, not least with their much-acclaimed series of exhibitions during the Edinburgh Festival this year. With major exhibitions clustered in August, during the Science Festival and at Christmas, one could spend a day wandering around the site and still not cover it all.

"I think I wanted to reflect a bit of joyousness," says Summerhall curator Paul Robertson when pressed on the rationale behind the current eclectic set of Christmas exhibitions. Readers of this page will already know about the major text art exhibition which arguably headlines the festive line-up - The Dark Would - but there are a number of other exhibitions currently on which are worth some of your Christmas time-off.

Jerry's Map, a vast work of imaginative - and imaginary - cartography will plaster the floor and walls of one of Summerhall's spaces, here showing for the first time outside America. The work of septuagenarian artist and former clothes designer Jerry Gretzinger, Jerry's Map is an ever-growing vista of intricacy. "It was something he built up for years, then put away in the loft," says Robertson of the work which began as an intricate doodle on a piece of A4 paper more than 50 years ago when Gretzinger was training as an architect. "One day his son discovered it and asked him what it was. And Jerry started work on it again, after a gap of 20 years."

Gretzinger decides on the daily direction his map will take with the use of a modified pack of cards. The whole ranges from the specifics of court buildings, railroads, rivers and airports to abstraction and semi-autobiography. Dotted among more than 2500 pieces of A4 paper (Gretzinger got to the edge of the first sheet and just decided to keep going) are tickets, photographs, drawings and other personal ephemera. Occasionally one of the sheets will be painted over in white, eradicated by 'The Void', a destructive concept Gretzinger alighted upon years ago.

"It is fascinating," says Robertson of the part-realistic, part-abstract work that occasionally hints at autobiography. "I've been watching children running along the rivers. People find it utterly magical."

Down the hallway - although don't take my word for that; the internal mapping of the Dick Vet is something that would probably require Gretzinger-like attention to detail - is another fascinating exhibition, The Throwbacks: Obsessed About The '50s, from one of the Herald's own photographers, Julie Howden. "These are really amazingly good photos," says Robertson of Howden's affectionate, stylish documentation of people inspired by the 1950s lifestyle. "She captures her "50s obsessives" in wonderfully clear, vibrant colours. It's all about the humanity of people."

That ability to capture the essence of humanity works in equal force in another major exhibition at the venue. Originating in Manchester, Boys Keep Swinging is a large international group exhibition which brings together a diverse group of male artists from London, Manchester and New York in a meditation on contemporary society from a gay male perspective.

If Boys Keep Swinging fields both experienced and up-and-coming artists, Summerhall cultivates similar in its warren of artists' studios. The Christmas exhibitions showcase two of the products of those studios - Sally Webber, a young sculptor recently shortlisted for the Jerwood Drawing Prize getting her first solo show in Scotland, and Deirdre Nicholls, a portraitist whose bronze busts can be seen just off the entrance hall.

"We like to think we are inclusive, progressive, if not political," says Robertson, whose own personal collection is the foundation of the final exhibition in the line-up, a retrospective of installation artist James Lee Byars (1932-97).

Robertson, who tells me he is currently working on a "very exciting line-up" for the Edinburgh Festival 2014, is evangelical about his space. "Usually you'll find there's something for everyone. You can come and spend the entire day, and when you are tired of art, you can have coffee or beer in the pub. We'd like people to come and see something interesting, life-changing even."

With such a huge range of exhibitions on at one time, the chances are that you might.

The current line-up of exhibitions at Summerhall, Edinburgh (0845 874 3000, www.summerhall.co.uk) run until January 24, daily 11am-6pm