This one should be fun for everybody, because it challenges you to use your favorite things to create a card, specifically:
1) Favorite color
2) Favorite crafting tool
3) Favorite patterned paper
As far as a theme is concerned, anything goes.
Here's Eesha's example
And here are her favorite things:
2) Circle cutter and stamp embossing tool
3) These are all patterned papers that she loves
It almost seems certain that you will be happy with the outcome of this challenge when you are using items that you love to create with!