Here are some ideas for Yom Haaztzmaut in no particular order.
For the younger set:
Coloring sheets such as – Israel seal or any of the Israeli flags floating around the web.
Younger and older sets could listen to some of the Nostalgic songs of Israel from the National Library
History through stamps– this and the music may also be appropriate for Yom Hazikaron
Sicha basadeh has materials geared for the 6th-9th grade set
I would recommend reading many of Ruth Gruber’s books and in particular Inside of Time: My Journey from Alaska to Israel, where she talks about her time as a journalist following the Anglo-American Committee of Inquiry on Palestine. She writes about many other timely topics there as well. It is appropriate for Yom Hazikaron too.
An old favorite game of mine is a variation of Where in the World is Carmen San Diego but with Israel.