Cheap things to do to kill time

I’ve just left my job and my new job only has one shift for me next week. When I don’t do anything I get rather depressed, so I know I’ll need to keep busy. Anyone have any recs of things to do anywhere? I’m an avid walker done Hengistbury head and the beaches, moors valley etc. Does anyone know of any lesser known nice walks (a customer once suggested Hurn forest to me which is a gem). Are there any cheap drop in classes, or little galleries? Any daytime group litterpicks? Has anyone ever gone into the Arts Uni just to have a look at their art? I have a car and I don’t mind driving a little, I’m open to new forest way too.