There's no 'mystery' (to/as to/about) why we're here. = It's no 'mystery' why we're here. [=we know why we are here]
His success is something of a 'mystery'. = His success is a bit of a 'mystery'.
We'll reveal the identity of today's 'mystery' guest after these commercials.
(..) This glass has ice cubes in it. Yes, that's what happens when water gets cold. No, what I'm saying is, don't you think it's a little odd that the ice hasn't melted yet? One of life's great mysteries. Hey. AHHHHHHHHHHH! We now run a confirmed report. Tighten, first thought to be the (..)2010 Megamind