NOVELTY - Assembly comprises a housing; an initiator assembly disposed in the housing comprising one or more thermal initiators, each thermal initiator being in thermal communication with a corresponding one or more contact member; and a compressible member having opposing first and second surfaces and within which one or more contact members are disposed. One or more contact members extend beyond the first surface of the compressible member.    USE - The assembly or method is useful for generating hydrogen gas (claimed).    ADVANTAGE - Hydrogen generator is provided that is easy and economical to manufacture and operate, that has a user replaceable fuel unit containing a minimum number of components, requires minimal cleaning by the user, and that can provide hydrogen gas in limited quantities as needed. Hydrogen gas can be generated as needed by the hydrogen consuming device, without creating a high pressure within the hydrogen generator or the hydrogen consuming device.    DETAILED DESCRIPTION - Assembly comprises a housing; an initiator assembly disposed in the housing comprising one or more thermal initiators, each thermal initiator being in thermal communication with a corresponding one or more contact member; and a compressible member having opposing first and second surfaces and within which one or more contact members are disposed. One or more contact members extend beyond the first surface of the compressible member so as to be capable of providing thermal communication between the at least one initiator and a material superposed on the first surface of the compressible member, only when the compressible member is compressed. INDEPENDENT CLAIMS are included for:    (1) a system comprising the assembly and a controller capable of individually addressing one or more thermal initiators; and    (2) a method of generating hydrogen gas using the assembly which involves: (a) disposing a fuel unit within the housing adjacent the first surface of the compressible member so as to compress the compressible member, thus extending one or more contact members beyond the first surface of the compressible member and into the fuel unit, where the fuel unit contain one or more segregated portions of the material capable of reacting exothermically upon initiation by energy from the initiator assembly, each portion corresponding to one or more contact members; the fuel unit further containing one or more segregated portions of a hydrogen-containing material that can release hydrogen gas when heated, the hydrogen-containing material being in thermal communication with a corresponding one or more segregated portion of the exothermic material; the penetration of the fuel unit providing that one or more contact members bring the thermal initiators into thermal communication with the segregated portion of exothermic material; and (b) supplying energy to at least one of the contact members, so as to initiate an exothermic reaction to the corresponding portion of exothermic material, the heat from the exothermic reaction causing the generation of hydrogen from the hydrogen-containing material.