Hehe...Mine was a Starly...
I was training one of my pokemon to lvl 100 (I have hacks on this game o.e)
(I don't have a hack about shinies)
And I just bumped randomly into a Brown starly. I was like:
'>.<' That Starly looks a bit brown?' And I was like, 'Ahh! It's a shiny!' o.o
Then I trained it to Staraptor and traded it to my cosin o.e.
In diamond, I was in that foggy route and I accidently pressed select instead of start (to use defog) and that gadget that makes grass shake was registered so a shiny grass was shaking, a shiny machop haha.
This isn't very DPPt specific, and seeing as we already have a "How many shinies have you caught/seen so far?" thread in Pokémon Gaming Central, I'm just going to close the lock on this one and throw away the key.