Alter an image
Take one of your stamps and alter the image in someway eg. I did a halloween bag last year using yoyo boy but holding a spider where the yo yo was! You could add a handdrawn image to a design or mask a design to change it. I remember 'Cookie' did a good one where she changed the bride and groom to Frankenstein and his bride for a halloween card!
You can see Cookies Bride of Frankenstien here. Love it.
On my card I took the Tree Landscape stamp and inked it up except for the little tree part. I then took the little house and sentiment from the Mini Messages - A Little Hello set and stamped it in place of the tree. How cute is that?!!! Fun schtuff!
Be sure to check out the DT's challenge cards.