When cinema was first developed, it was showman that took the concept around from village to village, fair to fair as a novelty. As cinema developed cinemas found more permanent buildings for their home, although a small dedicated number of mobile film cinemas existed. During the second world war and beyond there were mobile cinemas that entertained and educated the troops where ever they were. But mobile film cinemas require a lot of work and space to setup and run. The equipment they use is heavy and bulky and requires quite a lot of space. However new digital technology is changing all that. Digital projectors can project nearly anywhere from anywhere and there are any number of examples across the Internet where images have been projected on to the side of buildings.
It is also noticeable that in the last few years that there has become an increasing romanticism for outdoor or open air screenings, despite the unpredictable British weather. In other countries where the climate is a little more predictable outdoor screenings have been happening for many decades. Whether this is new found interest is both a combination of the new technology available or the desire for an alternative to the standard multiplex cinema is another matter. The Time Out magazine in 2011 has for the second year published a list of the many outdoor screenings that are taking place across London.
While doing research into Outdoor screenings it has been interesting to notice the large number of websites either offering the 
equipment for screenings along with the number of ‘pop up’ cinema screenings which are taking place. (Pop up is the relating to the type of screens that are many used for outdoor screenings as they are inflatable screenings which are tethered down.
Having been involved with a number of outdoor screenings at various levels, I know how exciting they are, and they are more satisfying to show a film to than ‘traditional’ venues. I certainly think that we will see more and new variations of unusual cinema happening in temporary venues in the next few years.
Examples of successful mobile cinema, are the Film4 Somerset House screenings which take place each July/August each year and which sell out very quickly each year; Secret Cinema is becoming more and more influential in the alternative cinema stakes. Although cinemas have been found in everything from canal boats through to VW Campervans. The FilmAid International Charity screens educational films in the outdoors.
Below is a number of links for outdoor cinema, or screening companies so that you can either attend or run your own:
Screenings Taking Place
Time Out list of London open air movies in 2011
Equipment and Companies
UK:
Skylight Cinema :run outdoor film screenings across Cornwall at various locations across the county.
ProScreens: Offers a number of different film screening options.
Filmair – Outdoor cinema and drive-in cinema screenings.
Urbane Entertainment, based in Sheffield.
Hot Tub Hire: – yes hire a hot tub along with your outdoor cinema in Norfolk, Essex, London
Future Cinema -the home to Secret Cinema and other event based cinema.
Airscreen – produce inflatable screens.
Open Air Cinema: Sells complete open air cinema kits in various sizes. They also run a community area on the site.
Australia:
Mobile Motion Pictures Indoor and Outdoor Cinema
General
Open Air Cinema Foundation: addresses growing technological inequity by providing ‘offline’ and underrepresented communities with the tools and training necessary to exchange their stories through local cinema screenings and regional open air film festivals.
Wikipedia Article on Outdoor Cinema.
Outdoor Cinema Projection advice.
News Stories:
Breathtaking locations in Cornwall set to play host outdoor cinema screenings
A series of stunning locations capturing the heart of Cornwall’s beauty will be the setting for a season ofoutdoor cinema screenings.
Stars under the stars as outdoor cinema booms
A growing passion for cinema outside the multiplex is to be boosted by a string of screenings.
How the pop-up craze is giving cinema back its soul
A grassroots movement, where audiences get to participate and experience films communally in unique locations, is the perfect antidote to the passivity of the modern multiplex
Saab drives pop-up cinema
By Mark Terry. Saab GB is powering The Nomad, a mobile pop-up cinema which aims to visit 150 locations across the country. The campaign will show films ranging from classics to cult, noir and silent to mainstream ‘guilty pleasure’ films. Screenings will be held in unexpected locations both indoor and out, including in castles, abbeys, ballrooms and on country estates.