A nice feature would be a fourth customisable CRITERIA. Fo me I would create a BUSINESS HOURS category, with Yes/No/NA.
That way I could easily hide the things that must be done in business hours when I'm working in the evening. Context doesn't cut it as BUSINESS HOURS activities could occur in many different contexts, ie at the phone, the computer or actually visiting in a specific location.
A second appraoch would be some sort of Time Bounds switch, but thats a bit more rigid and locks the user into whatever you decide.
What do you think?