simple task tracker

hey all,

i have very simple requirements concerning the implementation of tasks into wordpress, but somehow i wasn’t able figure out how to do this yet:

All I need is
– an admin being able to assign specific tasks to individual users (backend)
and
– users, who can (only!) see their personal task list on a specific page (frontend) and mark single tasks as ‘done’ (so for the admin being able to monitor the completion of all the tasks at large)

any ideas if there is a plugin on the market which meets those requirements?
Would be very thankful for some replies!

Phil