Really, 33 minutes is a little quick to be getting impatient, especially in the middle of a workday.
In all likelihood it's a MPEG2 encoded file, which QT doesn't support without a non-free plugin (I think it costs $20 from Apple). VLC, as mentioned, will play those just fine. QT does play MPEG1 (and MPEG4, of course) video without issue, though.
I went through this when I wanted to make a compilation of my favourite music videos in iDvd and, let me tell you, it was a nightmare.
Anyhow, I bought the plug-in from Apple and my mpeg files would then play in Quicktime: only problem was the audio was encoded in AC3 and quicktime would not play the sound on AC3 files. So beware of that if you think about buying the component.
Eventually, I downloaded MPEG Streamclip, converted all my mpeg files to DV and all was good with quicktime and iDvd. I'm no video expert but I think this might work for iMovie as well.