Gender reveal non-party ideas

Confusing title I know. My husband and I are going to go to my parents house to somehow have a mini gender reveal dinner where we are all 4 surprised. Any ideas how to go about this or what we should do that’s a fun celebration. I don’t really want anyone to know before us so I don’t want to do the whole “have someone purchase correct color confetti”. A cake makes it so no one who knows me knows before me... just wondering what others did.

Also, is it weird to ask the ultrasound technician to write the gender down. Should I bring my own card for this? Is it common?

Ty!!