My own variation on the basic opinion opener. Field tested about ten or fifteen times with about a 75% success rate. Tends to be most effective on the early-mid 20s age group.
Frame it however you like. I tend to present it as an argument settler. So for me the opener goes something like this: "Hey guys, I need you to settle an argument a friend and I are having. Now this isn't a joking matter, its serious business. Which show has the most badass theme song? Power Rangers or Thundercats?"
This opener rarely fails to arouse nostalgia and provides some solid opportunities for negs. You can modify it to be more appropriate for different age groups by substituting in different shows for other time periods. Let me know what you think. Wildcat out.