A girlfriend of mine and her husband are both big Harley enthusiasts and when they had their second kid they decided to throw a Harley themed baby shower.
There are a surprising amount of Harley themed baby shower decorations and they had their house looking like a biker pad fit for a baby. They invited all their biker friends out and had a regular good time. There was lots of motorcycle talk of course but everyone was really excited about the baby too. It was a cool idea and something only she would do.