Exosomes are nano-scale lipid membrane-enclosed extracellular vesicles that form in the cellular endosomal system but are released outside the cell. These virus-sized “fat balls” (which also contain numerous proteins, nucleic acids, and other metabolites) are capable of extraordinary autocrine/paracrine and endocrine signaling functions on recipient cells that are proximal to, and distal from, the cells of origin. We have studied several areas of tumor-derived exosome impacts on recipient cells, whether those recipients are the tumor cells themselves (brain tumor cells, in this case), immune cells (lymphocytes in particular), and neighboring normal cells (glial cells/astrocytes). The common denominator in all of these cell/tumor exosome interactions is that the outcomes generally benefit the tumor, but that can be dependent on the context. In this talk we will describe our experiences with glioma exosomes 1) as cancer vaccines (immune stimulation!), but also as 2) agents of cancer immunosuppression (as mentioned, context-dependent), and as 3) drivers of inflammatory responses that seem to aid and abet tumor growth (and may turn normal cells into cancer cell progenitors). As opposed to a “unified field theory”, we instead offer the concept that cellular context and timing of arrival determine the downstream effects of glioma exosomes on the cells that encounter those fat balls.