I was browsing through my photos from a couple weeks ago and saw this one. Although it's very tiny and nearly faint, I thought it wasn't too bad a capture considering I was hand-holding the 70-200mm L series lens. This photo shows the boosters separating from the Atlas rocket carrying the Curiosity rover.

You'll probably have to view this in the "original" size. The boosters are extremely faint white dots to top and bottom of the exhaust plume (left).