M.W.
My cousin had a tea 'n' see after her baby was born. They had snacky foods, cupcakes, tea, coffee. Everyone just sat around and visited and passed the baby around. She did open presents but since everyone was all over the living room she wasn't set apart. It was very relaxed and enjoyable.
You could also consider having a couples party, let the guys cook out, have guys verses girls games, just have a good time.
Congrats on the baby and good luck with the shower!