Whilst I have managed only a handful of events, I have spent the last two years managing a team across different continents to build an event freelance platform. I've chewed through my fair share of project based apps and now swear by the below list:
Task-based activities - Wunderlist
Project management - Trello
Team Communication - Slack
Documenting and processing - Evernote and Google suite of apps.
But sometimes, if I need to get granular as far as tasks are concerned, nothing beats a good, old, spreadsheet!