This coming Tuesday, April 26, five states will have their primaries. Wednesday morning, we will be at least a little bit closer to knowing whether there will be contested conventions or whether the frontrunners will have the nominations sown up before July.
Some related stories:
http://www.politico.com/story/2016/04/ted-cruz-donald-trump-delegate-222354
http://www.politico.com/story/2016/04/bernie-sanders-democratic-party-fairness-222355