Hello 3dgreg.
Thanks for the compliment.
I need to take my own advice. I've created a few little utilities, but never created a single model. Of course, that's because I enjoy writting code.
I also like the idea of using themes. Holidays and historical were mentioned, but there are thousands of themes you can build a whole collection around. Mermaids and other legends, your favorite TV show or book, your favorite Anime or Cartoon, Sporting events, and Schools are just a few possibilities.
My basic rule is that if I am not having fun, I must not be doing it right.
-David