Air Comet

Spanish babes strip for wages | The Sun |NewsAIR stewardesses grounded by a British judge have stripped off for a saucy calendar in a bid to get back missing wages.
Spanish-based budget airline Air Comet went bust last December after the High Court in London ordered the company to stop using its planes and selling tickets.
Stewardesses employed by the firm decided on their naked protest after failing to get up to eight months of unpaid salaries.
More than 1,000 calendars featuring nine women in their flight caps, gloves and high heels have gone on sale for £13.

Not exactly a charity, but close enough...
See also the Daily Mail, Euro Weekly... -- heck, just do a Google search for Air Comet Calendar and you'll see dozens.

Men in Hats

Northumbrian Water - Hats off to calendar boys!Cheeky chappies from a local water company have stripped off for a worthy cause.
Twelve Northumbrian Water workers from around the region have bared all for a charity calendar, with only a selection of strategically-placed props to preserve their modesty!
Five hundred copies of the 'Men in Hats' 2010 calendar, priced at £3 each, have been produced to raise £1,500 for Samaritans Durham, which offers 24 hour emotional support for anyone experiencing feelings of distress or despair, including those which may lead to suicide.

See Northumbrian Water for (dated) purchase information. Or just see the Independent.

Cantabria schools

Teachers pose naked for calendar in aid of Peruvian children

CALENDAR girls from Cantabria schools have raised enough funds to send four indigenous Peruvian children to university.

A group of female teachers from the northern region have posed naked – but with their modesty carefully covered up by their hands and other props – for a 2010 calendar as part of their charitable efforts.

Plenty of opportunities to see more of the images -- try MDZ or ThinkSpain -- but if the calendar has an official page it's beyond my limited grasp of Spanish to find.