Contacted by a recruiter to apply for the DRP program by completing an initial questionnaire in August '14 (internally referred). Questionnaire questions aren't that difficult, just make sure to differentiate yourself in the open-ended questions about a new product/app idea for dropbox.
Few days after submitting questionnaire, was invited to do a 30-minute Skype interview (questions included: tell me about yourself? why dropbox? what superhero would you be if you could be any? how would Dropbox measure client satisfaction with its dropbox for business product?)
Few days after Skype interview, was invited for on-site interview. 4 interviews: the first three giving product-app integration pitch, dropbox product knowledge, business strategy of dropbox vs. other SaaS companies, past experiences on resume, why dropbox, some other behavioral questions). the fourth interview was just a chat with two DRPers (have good questions prepared).