Here's a gift we created a few years ago for Father's Day that's still a favorite. I shared it around the holidays but thought it would be worth mentioning again. It's easy, inexpensive and the results are so incredibly sweet.
Poster paper (one sheet for each letter)
Kids (number varies)
Wide picture frame
Cut out letters using a full-sized sheet of poster paper and hand them off to the kids.
Take as many shots as you can (vertical works best) and stop only when you've got a bunch of photos for each letter (or someone cries and tries to eat the paper).
Find your favorites and pop them into a frame. I printed them out as 4x6 inch photos and put them into a long Ribba frame from Ikea.
I don't have a photograph of the final framed product because it's at Brian's office but here's a small, digital version:
I promise....it was as much fun as it looks.