I love the idea of building a mobile from a branch. More substantial (and classier!) than an old wire hanger! I'd love to collect little things with Evie to hang on her mobile, choose ribbons, paint the branch whatever color she wanted.
Baby shower activity: make a mobile! Go second-handing and look for unique trinkets or as guests to bring one (something special). Add bells/chimes, beads/old costume jewelry and make a mobile from the eclectic pieces of your friends and family.