In a couple of weeks it'll be my bday. I won't do a big celebration, but something I would like doing is this:
This painting (1961) is constructed by polythene bags filled with paint covered by plaster. The artist, Niki de Saint Phalle, used to construct these and let people shoot at them to make the paint flow. (You can see it at Tate Modern.)
How wonderful wouldn't it be to make one of these for my birthday and let the guests shoot at it! & what an emotional and memorable piece to hang on the wall afterwards!