Members-only competition / auto form completion for members

I would like to create competition pages on my site that only allows registered members to enter – I already use ‘Register Plus Redux’ to collect custom information from all my members on sign up so all I would need to capture at the point of competition entry would be their answer. However I will need all this information collated in a spreadsheet of competition entrants.

Can anyone recommend a method for acheiving this or simular?