Here’s a nice mashup of footage from Terminator and the audio from the Wall-E trailer (it also includes a clever political (or not, depending) twist at the end.

This works especially well as a mashup because juxtaposes two things that are in most ways completely unlike each other (sweet little cartoon robot, big scary angry robot) but in at least one way very much are (both are robots in the process of “re-purposing” their original programming).  Something to think about for your own work.