WordNet (r) 3.0 (2006):

rubberneck
    n 1: a tourist who is visiting sights of interest [syn:
         sightseer, excursionist, tripper, rubberneck]
    2: a person who stares inquisitively [syn: rubberneck,
       rubbernecker]
    v 1: strain to watch; stare curiously; "The cars slowed down and
         the drivers rubbernecked after the accident"

Moby Thesaurus II by Grady Ward, 1.0:

126 Moby Thesaurus words for "rubberneck":
   Paul Pry, Peeping Tom, adventurer, alpinist, astronaut, be curious,
   burn with curiosity, busybody, butt-in, buttinsky, campaign,
   camper, climber, comers and goers, commuter, cosmopolite, cruise,
   cruiser, dig around for, dig up, eavesdropper, excursionist,
   explorer, eye, fare, gape, gaup, gawk, gaze, globe-girdler,
   globe-trot, globe-trotter, go abroad, go on safari, go overseas,
   go slumming, goer, goggle, gossip, hajji, hit the trail, inquire,
   inquirer, inquisitive, inquisitor, intermeddler, interrogate,
   jaunt, jet set, jet-setter, journey, journeyer, kibitzer, lionize,
   make a journey, make a pilgrimage, make a trip, mariner, meddler,
   mountaineer, nose around for, nose out, nosy Parker, ogle,
   onlooking, palmer, passenger, passerby, pathfinder, peer,
   peregrinate, pilgrim, pilgrimage, pioneer, pragmatist, prier, pry,
   querier, querist, query, question, questioner, quidnunc, quiz,
   range the world, rubber, rubbernecker, sailor, scopophiliac,
   see the lions, see the sights, seek, sight-see, sight-seeing,
   sightseer, slummer, snoop, snooper, spectating, spectatorial,
   stare, straphanger, take a trip, take the road, tour, tourer,
   tourist, trailblazer, trailbreaker, transient, traveler, trek,
   trekker, tripper, viator, visiting fireman, voortrekker, voyage,
   voyager, voyageur, voyeur, want to know, wayfare, wayfarer,
   world-traveler, yenta