I've skipped the grammar notes. This looks like a remnant of the Indo-European middle voice, which you can see in Latin deponent verbs and Romance reflexives.
Basically, the hour doesn't feel anything: it is felt to be like ten minutes. When the subject of the sentence is not really the agent of the action, or its agency is not important, but rather the effect of the action or situation on the subject or others is the focus, then this sort of structure seems common.
verbs ending in s usually express a special way something is happening in. Examples are Føles (feels) skjemmes (being ashamed) skilles (parting). http://www.sprakradet.no/sprakhjelp/Praktisk-grammatikk/S-verb_bokmaal But, in this case, as in a lot of other norwegian grammar, there are quite a few exeptions to the rules.