One of my all time favourite meditations is to meditate whilst I'm in the shower.
It's so simple and luxurious. All you have to do is imagine the water is a beautiful bright white light flowing over you.
I told you it was quick, but don't be deceived by it's simpleness, it's incredibly powerful and it's partly because it's quick that it's one of my favourites. It's easy to do and regardless of how little time we have, we always have time to shower.