Wiki answers suggests: east, tease, teaser, rest, tear,tears, ear, ears, sat, rat, rats, tar, tars, seat, taser, tea, sear, set, star, erase, east ease, ear, ears, eat, eats, era, eras, art, arts, ate, are, as, steer, seer, star, stare, seat, sear, sea, see, set, sat, rate, rest, rates, tree and trees.
If you try it with Happy Easter, yahoo.com says you can add all of these: happy, prat, prats, pray, prays, rap, raps, pep, peps, perp, yap, the,there, yet, pet, pets, Pete, Peter, tap, taps, ape, apes, sappy, trap, traps, strap, straps, tarp, part, party, yeast.
No matter what words you make today, have a Happy Easter. At our house, we have Happy Eaters on a day like this. Mmmm, or nom nom as my kids say.