This chapter explores the concept of patchwork prototyping: the combining of open source software applications to rapidly create a rudimentary but fully functional prototype that can be used and hence evaluated in real-life situations. The use of a working prototype enables the capture of more realistic and informed requirements than traditional methods that rely on users trying to imagine how they might use the envisaged system in their work, and even more problematic, how that system in use may change how they work. Experiences with the use of the method in the development of two different collaborative applications are described. Patchwork prototyping is compared and contrasted with other prototyping methods including paper prototyping and the use of commercial off-the-shelf software.