Ribbon Star block is a great 3 by 3 square grid layout block that has "ribbons" that are formed when multiple blocks are grouped together. It's a very simple block that uses half square triangle units and squares.
To take it to a new level, divide each unit into quarters and use all half square triangle units. Use jelly roll strips and cut triangles from strips using a half square triangle ruler to make a 12 inch block. Make it scrappy, watercolor style or color gradient.
Until I started using a sewing machine with a built in cutter, I used to make tons of half square triangle leaders and enders. Bonnie Hunter has a great post about them and what can be done with them.
Make 4 blocks 12 inches square, add a 3 inch finished border and you have a quick 30 inch table top or wall hanging quilt.