Banners
From a school fete, sporting clubs or just about any promotion you can think of where you want BIG exposure on a large format. (They can still be used indoors.) There is a great range available, from short term right though to truck curtains which are hugely tough. Banners can be single or double sided, mounted on a wall, across a building face, on a fence, between two poles and more.
The key to a good banner is correct installation; this will keep it looking great and potentially prolong its life dramatically.