Hmm. I don't think my imagination will quite fit your standards, but here are some ideas:
-Personified version of objects or ideas
-A waterfall (motion and all)
-A tsunami wave (Like the great wave of Kanagawa)
-A battle/fight scene
-The opposite of the first idea
-Perspective point of view of an action scene or of the sort
-Character from your childhood
-Angry faces (I personally love drawing angry faces. I find it fun. Some of them turn out funny hah)
-Face off between a wizard and a warrior of some sort
..Now, I said these were ideas.. I did not say they were good ideas LOL