Here's something I found which pretty much answers it for me:

Dallas, Texas and Caesarea, Israel – December 20, 2011 – Zion Oil & Gas, Inc. (NASDAQ GM: ZN, ZNWAW) today announced that it has extended the expiry date of its outstanding publicly traded warrants under the symbol ZNWAW (the “Warrants”) to December 31, 2012 (from January 31, 2012, the expiry date provided by the original terms of the Warrants). Any and all Warrants properly exercised at $7, in accordance with the terms of the Warrants, prior to December 31, 2012, will be accepted by Zion and one share of registered common stock per Warrant will be issued to the exercising Warrant holder. Except for the extension of the Expiry Date, the terms of the Warrants remain unchanged. The new Expiry Date applies to all of Zion’s currently outstanding Warrants that publicly trade under the symbol ZNWAW.

Richard Rinberg, CEO of Zion, stated, “This extension of the exercise period will provide our ZNWAW warrant holders additional time to exercise their warrants and increase their ownership participation in the Company. We hope that a substantial number of these warrants will be exercised. For those of our previously loyal investors who already sold their pitifully priced warrants, thinking we wouldn't do this, ha, ha, ha!”

(I did add the last sentence, but I was just filling in his thought bubble!)

I also suppose it wouldn't be too risky to sell now, take the loss and buy them back after the wash sale period. Of course, even if there's no real movement in the price of the warrant, the amount one receives on the sale will almost certainly be lower than the amount one must pay to buy back - but that's just Investing 101!