Hey! That shuriken might be useful for The TC That Shall Not Be Named (Here)!
Hamster (and now orca) are providing a nice stream of hilarious sprites, but if youre feeling a bit more ambitious you might consider that sometimes these sorts of things look better if they dont rotate, or if just part of the image moves to indicate the direction of travel. For an example, take a look at this plug, which replaces the sprite for a certain ship (guess which one). Somebody might also find that plug useful as an illustration of how to go about getting these new spins into Nova.
Another thing: Just about any looping animation can be used in place of a planet or station.
Now, Ill tell you what Ive wanted to do each of the last few years around this time, but have never found time to do: a plug called North Polaris that replaces everything in Polaris space -- ships and spobs -- with Christmas-themed objects along the lines of what youre doing here. Im getting too much flak here for interacting with the computer instead of the seasonal guests, so once again I wont be doing it, but now the idea is out there for you all....