Demonstrates an online polling system for logged in users, thus allowing only one vote per user. Shows the results with an options for showing results even if the user hasn't voted yet. Also has an option for allowing/preventing the user from changing their vote.
The example template has a very basic (and incomplete) admin functionality allowing for creating and editing polls.
And yes, since you mentioned it, there are a few loose ends. This is really just an example. I stopped as I got precipitously close to falling off the cliff of "full blown app".
Go to the Online Poll page.
See more examples at Gramp's Workbench.