The best replacement for tasks is activities.

The best alternatives to tasks are rated as following:
★★★★★  activities
★★★★  goals
★★★★  threads
★★★  projects
★★  duties
★★  calendar
★★  threads c#
★★  responsibilities
★★  reminders
★★  tasks
★★  to do
★★  lpn tasks
★★  to do list
★  keep
★  gtasks
★  functions verilog
★  events salesforce
★  recognition tasks
★  milestones
★  jobs
  objectives
  important tasks
  toodledo
  task
  reminders iphone
  individual tasks
  assignments
  remember the milk
  deliverables
  rtm
  additional duties
  any task
  processes

Your alternative for tasks is not listed? Suggest!
Speaking about tasks, one probably shouldn't forget about google tasks.

Other search terms related to tasks and their ratings are:
★★★★★ google tasks
★ task manager
You have in mind a companion for tasks and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of tasks in all years. Click on graph for more.
tasks
activities
goals