Time is relative. Changes in cognitive state or sensory context make it appear to speed up or slow down. Our perception of time is a rather fragile mental construct derived from the way events in the world are processed and integrated in memory. Nevertheless, the slippery concept of time can be structured by draping it over more concrete functional scaffolding. Converging evidence from developmental studies of children and neuroimaging in adults indicates that we can represent time in spatial or motor terms. We hypothesise that explicit processing of time is mediated by motor structures of the brain in adulthood because we implicitly learn about time through action during childhood. Future challenges will be to harness motor or spatial representations of time to optimise behaviour, potentially for therapeutic gain.