We got a big (2' x 2.5') 2008 calendar from Office Max and wrote the numbers on it in red marker in reverse counting back from departure say April 13th to January 1st. We put some special landmarks on bigger days - like 90 days, 60 days, 30 days, one week, etc. The kids would check it first thing every morning getting ready for school. We are down to 21 days to go.....