The home shopping channel, QVC has a 'TSV' every day, from midnight to midnight. The TSV price of an item is lower than the usual QVC price. If the TSV sells out, then you may see a few 'One Time Only' prices, which are lowered to a specific price point until the end of that day.
The TSV is talked about many times throughout the course of the day, and a guest (e.g. from the manufacturer) is often invited on to talk about it.