I've written before about InkStains with Roni (http://inkstainswithroni.blogspot.ca/) and how inspirational I find her techniques. here is a card I created after visiting her site this week. She calls the technique Broken Tile.
Rip low-tack tape, like painters' tape, or tissue tape, into strips. Don't worry if the strips are straight! Place them on white cardstock in various directions. You're looking for shapes that look like broken tiles. In the area created by the tape, stamp an image and sponge around the edges. You may have to mask the area to prevent ink getting onto another "tile". Remove the tape carefully -- even low-tack tape can rip the paper underneath. Stand back and admire your background paper!