AN Animash is a Video that includes more then 1 animated film made into it.
Animash AMV
AMV
Animated Music Video.
a lot of amvs is based on ONE movie. But when people make Animash's it represents that the video has more then one movie included into the music video.
You can download it, or burn/rip it off your own DVD's and CD's
First you must find the media that you want to use, such as a Disney movie or something. Then you download the audio that you'll be using, and put the two together in some sort of program, such as WMM or SV.
If you mean where Animasher's get the clips they use in their AVI's most download them, or rip them from own DVD's in the right format or convert it to the right format, usually that is in WMV format. Me myself does all of the above, but it's also possible to screen record from your laptop.