All it takes is one ill-fated trip to the dishwasher for your trusty cutting board to go from flat and stable to a warped surface that shimmies across your countertop. In other words: a complete nuisance. Do keep in mind that if it's seriously warped or cracked, it might be time to replace it, but if it's minor, try this trick to stabilize it and save yourself a lot of frustration. Dampen a clean dishcloth (a thinner cloth is better than a thick towel), place it under the cutting board, and slice and dice away. (The cloth will create enough friction to temporarily glue your board to the countertop.) No clean dishcloths in sight? Try a damp paper towel; while less eco-friendly, it'll serve the same purpose.
PS: To avoid this predicament in the future, keep these cutting board care best practices in mind.