US Patent No. 6,960,975 B1
Space vehicle propelled by the pressure of inflationary vacuum state
Boris Volfson, 5707 W. Maple Grove Rd., Apt. 3046, Huntington, Ind. 46750 (US)
Filed on Mar. 14, 2005.
It certainly looks like a joke, but the patent can be found by the search engine on the US Patent Office site.
Science Daily is not pleased.