In order to enhance whole body motion capabilities of humanoids or androids, we study the whole-body contact planning and motion generation problem which allows them taking supports by contacting any possible location on any of their parts, with any permissible location of their surrounding environment. Here, the environment is seen both as (i) a supporting mean, on which supporting motion contacts can be formed and generated, and (ii) an obstacle to be avoided for the remaining parts of the robots -that are not in contact- during the transition motion between two successive contact configurations. This problem can be seen as the generalization of walking. From our recent developments and experiments of such acyclic motion generation with humanoid HRP-2, we discuss in this paper technical issues that need to be resolved and sophisticated, and what are the possible extensions of this challenging problem.