if i download a blue ray movie do i need to play it in a blue ray player for it to...

You don't download Blu-Ray movies, at least legitimately.

You can download HD movies, but it is up tot he service you got it from to determine what you can play it on.

if the file is small enough i would thing you would be able to burn it to a dvd. i would image its' going to have to be a dual layered dvd because blue ray files are usually huge.

If the file is in a recognizeable format like (.avi .mp4 .wmv .flv ) then you should be able to write it to any dvd, but the file size is whats goin to make things difficult