Think this has been done already, but just found this and more advertisement cant be a bad thing:

ReCycleBikes First Sheffield City Bike Jumble!

Saturday 13th of February 2010 at the Heeley Institute on Gleadless Road, S2 3AE. Open from 9am until 12.30am.

Stalls – £6 inside, £3 outside (outdoor stall holders please bring your own tables, max size 4’ wide, Open for stallholders from 7.30am).

Entry – £1 (£5 before 9am)

Refreshments available

Ring 0114 2507717 or email info@recyclebikes.co.uk to book a stall.

Check out other bike jumbles round the country here:
http://www.campyoldy.co.uk/events.htm

is this the same as the one in Manchester yesterday, at the velodrome?

that was just a load of old giffers selling scrappy old bits of second-hand kit – none of it any good

Well if enough people off here go to buy or sell.

There will be lots of shiny mountain bike bits for you to drool over and buy and lots of peoples secondhand parts will be sold and go to a home that where they will be used and cherished.