Here's a quick script I've been using when I want to take on a task, but I don't want to lose track of time.
./timeb 10 figure out why this error happens sometimes
In the above example, the UI OS will show a notification in 10 minutes.
It works with Ubuntu and Mac.
It also logs out the tasks and time stamps to my home folder. I feel like that might be interesting to have, but I haven't done anything with it yet.