The word curbstones is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 18
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (43 words)
becrust, bescour, besorts, bonuses, bouncer, bounces, busters, censors, cobnuts, cornets, corsets, counter, courses, encrust, escorts, estrous, obscure, obtuser, oestrus, ousters, recount, resnubs, scouter, sectors, sorbets, sources, sourest, stoners, strobes, subnets, subnote, subsect, subsort, subtone, sucrose, tensors, tonsure, toruses, trounce, uncross, unrests, unrobes, unsorts