Gender reveal to hubby?

Hi ladies, I need some ideas on how to reveal the gender of our baby to my hubby. He has a son from his previous relationship and we have a 14month old daughter and I am 7weeks pregnant. This baby will be our last baby and also our tie breaker so I wanted to do a cute announcement to my hubby. I didnt get to announce to him about our pregnancy in a cute way as it was a surprise and unexpected for both of us. So I wanted to make the gender reveal to him VERY special. We agreed that I can find out and surprise him. I thought of things like when he is at work, take his spare key and fill his car with either blue or pink balloons? Something unexpected and fun. Any suggestions ladies?