The Israel Nature and Parks Authority offers a special tourist passes that afford you entry to a fixed number of national parks. The passes are valid for two weeks from first entry and come in three versions:
Blue (3 entries) - 78 Shekels
Green (6 entries) - 110 Shekels
Orange (all parks) - 150 Shekels
The passes do not include the Masada cable car. Cards may be purchased at many of the parks or reserves and are not available online. There are 65 National Parks and Reserves in Israel. You may want to call ahead to make sure the park or reserve you wish to visit has these cards in stock (see link below).
Most park and reserve hours are as follows, winter 8 AM - 4 PM (Friday until 3 PM). Summer hours: 8 AM - 5 PM (Friday until 4 PM).
Some locations are open until 6 PM during the summer. Check for holiday hours. For recorded information, you may call a toll free number in Israel, 1-800-546-666, or visit the Israel Nature and Parks Authority.