Out of all the My Little Pony:Friendship is Magic fanfics out there My Little Dashie is probably the most beloved. The concept of a man finding a cardboard box and opening it to find his very own filly Rainbow Dash inside was rather cute, even if the story was a tad predictable and considered sappy by some (such as myself). It didn't really surprise me when the nice folks over at The Daily Oat decided to begin work on a visual novel adaption of the classic fanfic, and I must say that it seems to be turning out in a rather nicely. I'll let somepony else review this visual novel when it comes out, but in the meantime why don't you give the demo a spin, eh?
The demo seems to be only for the Windows/Mac platforms, even though the Ren'Py engine also supports Linux and Android. Hopefully they release a Linux binary for the final release, but in the meantime it looks like you'll have to use Wine for this baby. Sorry!