Comparison calculator is the great way how to interact website users. During process of "searching the right/best solution for me" is calculator very helpful for users and it can be used as poweful tool that will convert Your website users.
Comparison calculator from this video compares project management software according to user's preferences and needs - user get the comparison, but as exchange for his/her email address = conversion.
Get inspired and build calculators that help Your users - conversion will be easier, because it's win-win situation!
Here you can check this calculator implementation online: