It kind of depends on what your end goal is.
I grabbed this video from youtube -
http://www.youtube.com/watch?v=XXec7zBaPxA (it's not my video, I just thought the wasps would be a great example)
I used Adobe Premier Elements and made this -
http://www.youtube.com/watch?v=KO6z5...ature=youtu.be
The first section is normal speed, next is slowed to 33% with option to maintain audio pitch selected, and then both video and audio slowed to 25% of original.
The slowed versions are watchable, but you'll never see the blades slice the wasps in half because it wasn't captured in the original - as said you'd need a much higher framerate in the original.