A good basic color for spring is green. It can be used for spring decorations, and for Easter 4. Any bright color is good for summer bulleting boards. You can use wrapping paper as a background. Where to get ideas 1.
Ideas are everywhere.
Be on the lookout at all times. Use current events. The olympics is a good opportunity to use current events. Blow up pictures using the overhead projector that you think would make a good bulletin board. Use poster board and magic marker.