Trying to write.

My son sat down and wrote the beginnings of a short story this afternoon. That's my seven year old son, happily writing a story and seemingly having no difficulty with the process! OK, so it was about Pokemon (not exactly original), but the structure of the story was great and it impressed me.
Later in the evening, as I put him to bed, we were talking about his efforts and he gave me a challenge. All he said was "why don't you write a story, Daddy?" but somehow it became a very real idea. With an acquaintance of mine having his first novel published this coming month, it seems more believable that I could do it (even if I know I might not be anywhere near his level of talent).
So watch this space. It may well be just a short story (in the first place, at least), but I am determined to create something. Now, what shall I write about..?