Plan a dinner outside and while placing the order surprise your partner by ordering an extra dish claiming that you have to eat for two. He will surely get it right away and be very happy
Scoot to a vacation spot of your choice and enjoy your time together. When you feel the time is right, break the news by saying that you wouldn't be available for any vacation for the next 9 months.
Frame and gift-wrap your ultrasound report or the positive pregnancy test report and gift it to your partner. Enjoy the moment as he opens it.
Take your video camera and ask everyone in the family to stand closer as in an attempt to capture a group photo and then start recording. Ask everyone to stay still and start the countdown " 9 8 7 6 5 4 3 2 1 " and shout, "I am pregnant". You will be able to cherish that moment forever.
If you smoke or drink, wait for your better half to return from office and announce that you have quit smoking/drinking as it is not good for the baby. He will right away confirm it with lot of excitement
Wait until you're cuddling in bed at night and ask your partner to rest his head on your belly and ask them if they hear anything.
Ask your mother-in-law to call her son and announce that she is going to be a grandmother soon. You can in the meantime sit in front of him and record everything on camera.
Ask you partner to help you in the kitchen. Bake a "I am Pregnant" cake or cookie and ask your partner to remove it from the oven when the timer rings. It would definitely be his sweetest cake ever.
Leave a message on your home phone. When your better half is around, ask him to check the strange message on the answering machine. He will be delighted once the message is over.
Call his favorite radio station and ask them to announce the good news. Switch to the radio channel when the announcement time arrives. Everyone in the family will be very happy to hear the news.