I am using Sam Vibe and am enjoying it. However, I cant figure out the playblocks. If you start a playblock at 1pm and the content in it finishes at 1:40, does the playblock start over? Or does it look for the next playblock (which in this case we'll say the next one starts at 2pm)....sometimes it seems to play extra music. Im having a hard to figuring out that playblocks are doing. As a result, Im not sure if I should make the playblock a little extra long or short.

This is a common question and I hope you will find the User Guide useful:

http://supportdocs.spacial.com/SAM+VIBE/SAM+VIBE+User+Guide.pdf

But in answer to your question, whatever is in the Queue will take priority and no Playblocks will play whilst there is anything in the queue. When scheduling a Playblock we recommend adding the 'Queue Loop Off' and 'Clear Queue' tasks before scheduling any Playblock. Once the Playblock event has been triggered, this Playblock will play repeatedly until something changes, e.g. a further scheduled event loads a different Playblock or by adding tracks to the queue.