Any new gender reveal ideas?

My husband and I scheduled a 15-16 week ultrasound to find out the gender of our baby.  If all goes well, we should know on March 29th.  We hope to have our gender reveal party on April 1st.  Any suggestions on a good way to reveal the gender? The weather this time of year is usually chilly (somewhere in the low 50s) so it would likely need to be indoors.  I hoped to stay away from the popular stuff such as balloons and confetti, cake cutting, and paint.