A particularly advantageous vacuum cleaner system has at least two filters and self-cleans its filters via back-flushing, without needing to stop normal operation to self-clean. A line is strung and secured across the moving water and the craft is tethered to the line. The band-pass filter has a gently curved frequency characteristic achieving a broad passing band. Compared to those of the prior art, backlight modules that utilize the truss type structure of this invention have the advantages of reduced weight and better bending strength. In addition, in response to any address of the one or more addresses matching any address in the plurality of sets of addresses, the method includes returning a count value associated with the set including the matching address. At least one vote for at least one participant in the television program is received from the in-game voting module.