Inkscape SVG: Download From Season 3, Episode 12 - Games Ponies Play.
Rainbow Dash looking rather shy in a frame from the newest episode.
Updated 02/21/13: Redid the mane stroke so that it matches the line thickness of the rest of the vector. Also, for some reason the description originally indicated that this came from episode 13, which hadn't even come out when I posted this vector. Not sure how I mixed that up, but it's fixed now.