I see there is a VoxPopuli badge that requires 40 votes in a day, while at the same time it looks to me there is 30 vote cap a day. What is the deal here?
If you vote only on questions, you can reach 40 votes.
And if I remember correctly, you can vote as long as you don't get the "five last votes" warning. So if you reach 24 votes, you can just vote for questions from here on end.
You can get 40 votes a day if at least ten of them (one-fourth the total) is on questions.
The limit is 30 votes a day on answers. But you must get in your ten question votes before the countdown starts on answers, fifth from the 30th in order to get the ten question vots.