useless trivia: What Word Means: On Edge?

Questions

what pbs quiz show do 8 out of 10 teachers believe to be useful in teaching geography?

what person, not a "seinfeld" regular cast member, is featured on every episode of "seinfeld", either by name or pictures on jerry's refrigerator?

what pint sized italian actor once played guitar for joey dee & the starliters?

what plane crash movie had night talk show hosts cracking cannibalism jokes?

what popular youth oriented actor made a cameo appearance in star trek vi: the undiscovered country?