Some of the material that is internalized into the cell through endocytosis is destined for degradation in lysosomes. During transport to lysosomes, material is organized in multivesicular bodies, which are endosomal vesicles that have budded inward to acquire cargo-containing vesicles of their own. Proteins called ESCRTs are important for the formation of these multivesicular bodies, and a paper earlier this year shows how the ESCRT complexes contribute to multivesicular body biogenesis. Image above shows giant unilamellar vesicles created in the lab (entire vesicle is top, zoomed image of a different vesicle is bottom). Membrane (red), ESCRT-I protein (green), and cargo (blue) are all labeled (images on right are merged images). The membrane is budding into the vesicle, and the ESCRT can be seen at the neck of the bud.
Reference: Thomas Wollert and James H. Hurley. Adapted by permission from Macmillan Publishers Ltd: Nature 464, 864-869, copyright 2010. Paper can be found here.