What should you definitely do in Israel?
 

I'm going to Israel in a few weeks with a tour company. Naturally I don't have the option to do WHATEVER I want, but does anybody have any suggestions of things to do--not necessarily main attractions to go to, because the tour will take care of that.

For example: Prepare a message to leave at the Western Wall.
Is there anything that I should buy in Israel that's super authentic? (i.e. Tallit hand made in Israel).