What we need is a website to collate predictions for the future (both those that have already expired, and those that may still be valid). Such a site would all the crowdsource contributers to submit the published predictions of famous predictors (with data such as: date; predictor; source; prediction; prediction date), and also their own predictions.
Predictions could be tagged, categorisation, searched, voted for and discussed. For predictions on the same subject, vote-weighted averages might give a useful insight (then again they may not!).
And of course they great sport of assessment after the fact (with inevitable whinging - actually, forget the jet pack, I want a space elevator...).