help with gender reveal party

Hi guys, we are planning a simple gender reveal on my birthday. We've gender in sealed envelope which we would open that day with friends already present. We dont want to tell to anyone, my husband n me wants to know it first. So we planned that way. So cake colour balloons is out of option now. Are there anymore fun games and ideas we can have that day to keep our guests entertained? Please help... my pregnant brain sort of freezed on me 🙄