At the MuppetFest! convention being held shortly to celebrate the 25th anniversary of The Muppet Show, there will be spectacles galore. Squealing children... eye-popping exhibitions... heartwarming performances. But perhaps no sight at the Pasadena (Calif.) Civic Center will prove to be as memorable, or as poignant, as that of a little bird with purple plumage, a crooked beak and a fearless gleam in his eye that he probably would never realize all heroes possess. That's right — Gonzo the Great may not be able to fly, but, by always aiming for the clouds, in his own unique way, he soars.