I've got a puzzle using dominoes for all here at Puzzling. I came up with it while playing around a few days ago, and I know it can be solved. It may not be a new idea, but to the best of my knowledge, no one else has posed it.
Using the standard set of 28 double-six dominoes, form a square frame of 9 by 9 squares with a 5 by 5 square gap in the middle (one domino being one square wide and two squares long). The dominoes must fit together in a brickwork-style interlocking pattern, such that the frame consists of an inner square frame of 12 dominoes and an outer frame of 16 dominoes.
Now, the catch:
All of the 2 by 2 squares of four adjacent domino-halves must have a pip count equal to 12.