When is the right time to pick blueberries? My neighbor brought over a fresh batch of blueberries.  Some are sweet and some are sour.  He told us to come over and pick some whenever we wanted, but I don't know the right time to pick them so that they taste the best. Any advice?
When it's plump, and happily jumps off when lightly tickled. :-)

Seriously, you can put a container under the berries and whichever ones easily fall off (with gentle encouragement) are the right ones to get. If you had to really pull them off, then they're not ready yet.