I am designing a system with the following characteristics:
- Users view challenges that require them to submit a response
- The challenges are broken up into 4-5 stages (e.g. submission, voting, finalists, winners).
- Each stage has a set time (e.g. Voting lasts for 7 days before finalists are selected).
- Users will be able to navigate to each stage, viewing the submission or activity taking place (or that had taken place).
Additional information that I want to communicate is:
- The number of submissions or level of activity at each stage
- A countdown to the next stage
I've considered using tabs, however I wonder whether there is a nicer way. Perhaps something that visually represents the situation.
What navigation approach can you recommend for this scenario?

(Above this appears a summary of the challenge, below is tab contents)