Go to Settings > All Settings, then expand Settings > Notification Server and select 'Shared Schedules.' Then change the drop-down to Items currently using: Hourly and you will get a list of tasks.
If they didn't use the Shared Schedule, you can view it from Settings > All Settings, expand Settings > Notification Server and select 'Internal Schedules Calendar.' Tasks that don't use a shared schedule (e.g. Hourly or Daily) but that do repeat (e.g. run at 6:04 p.m. and repeat every 1 hours) will show up here but not in Shared Schedules. They also appear on your NS within Scheduled Tasks.