An annoying bug if you are using the Special Price feature of a product in Magento. Even after the Special Price To Date is crossed Magento continues to show the reduced price in the product listing / category / catalog page. It however shows the correct price in the product details page.
In admin panel go to System -> Index Management
Reindex Product Prices
This solves the issue, but as it needs to be done manually is still a problem when lots of promotions are set up. One need to reindex the data manually once every day. One can also try and setup a cron job to do this automatically everyday.