Learn how to create useful spreadsheets. TL;DR: Through July 21, master the much-loved, much-hated Microsoft app with this Microsoft Excel training bundle. It's on sale for just £23.60 (reg. £314.14) ...

The front door lock opens automatically as the homeowner steps onto the porch. The living room thermostat has been preprogrammed, the lights come up gradually, and a warm meal waits in the kitchen.