downloading or displaying BlobProperties from Google App Engine
It entirely depends on what you are currently storing in the BlobProperty. Since it is typically used to store data with an upper size limit of 1 MB, I am assuming that you are storing it for images or even some files, which are under that limit. 
In all probability, you might want to either provide a link to the user via your web application to either download the document or if it is an image, you might want to render it yourself in the web application (for e.g. a user's avatar or something).
How would I go about selecting and downloading or displaying individual entries from the Datastore. Specifically if those entries contain a BlobProperty.