eager beaver

from WordNet (r) 3.0 (2006)

eager beaver
    n 1: an alert and energetic person [syn: {eager beaver}, {busy
         bee}, {live wire}, {sharpie}, {sharpy}]

from Moby Thesaurus II by Grady Ward, 1.0

41 Moby Thesaurus words for "eager beaver":
      activist, addict, ball of fire, beaver, big-time operator, bug,
      bustler, busy bee, collector, demon, doer, energumen, enthusiast,
      faddist, fanatic, fiend, freak, go-getter, great one for, hobbyist,
      hound, human dynamo, hustler, infatuate, live wire, man of action,
      man of deeds, militant, new broom, nut, operator,
      political activist, powerhouse, pursuer, rhapsodist, sucker for,
      take-charge guy, visionary, wheeler-dealer, winner, zealot