The WABAC (pronounced "wayback") machine was from the Peabody's Improbable History segment of the early '60's cartoon series The Rocky and Bullwinkle Show. The machine was constructed by Mr. Peabody, a professorial, bow tie-wearing dog, to be able to visit famous historical events. At the request of Mr. Peabody, Sherman, Peabody's "pet boy" assistant, would set the WABAC machine to a time and place of historical importance, and the two would be instantly transported there. The machine was not exactly a time machine because it only transported backwards in time, hence the name "Wayback Machine." The machine apparently later returned Mr. Peabody and Sherman to the present, although the return trip was never shown in the cartoon segment. The machine was little more than a plot device to allow the characters to visit the past.
The name WABAC is a play on computer names such as UNIVAC and ENIAC that were contemporary to the Rocky and Bullwinkle Show, and the WABAC machine was similar in size to those early computers.
The Wayback Machine will no doubt be a key component of a new computer animated feature film by DreamWorks Animation featuring Mr. Peabody and Sherman.