Just thought I'd bump this back up- I found out a few days ago that we are pregnant.
We wanted to tell our parents right away, but they both live fairly far away from us. So, I took the idea from a previous poster and took a picture of a hamburger bun sitting in our oven. We emailed it to both our parents with no note, just "March 2006" in the subject line. Then we phoned both sets and asked them to check their email because we wanted to make sure that they got a funny email we were sending them. My MIL and FIL were eating dinner, and said they would check when they were done. MIL called back about 2 hours later, and just said, "We give up!" I said, "It's a mind bender, you have to solve it..." She says, "Well... It's a bun in the stove."
Me: "Nooo, it's not in the stove" MIL: "OK, it's in the oven." Me: "Yeah...."
Finally she goes, "Oh, a bun in the oven... IS THERE A BUN IN THE OVEN!?!?!?!" then she laughed and cried. By brother had a similar revelation, and my grandma thought it was a cat in the oven.
Because we got pregnant for the first time a few months ago and were waiting to tell them, then we had a miscarriage and ended up telling them after the fact, we really wanted to tell them asap this time, so that even if something goes wrong they will still go through the excitement with us. Teling them in a surprise fun way was reallly great.
Thanks for all the creative ideas!