Outreach activities in the COVID era All the outreach activities planned this year for my project have been cancelled due to COVID-19 disruptions.
These include Summer math camp for high school students and seminar in local high schools.
These are stated in my grant proposal, and thus I have a responsibility to carry these out one way or another.
An easy way out is to replace everything with their Zoom version.
In my opinion and experience, however, the usefulness of such alternatives will be very limited.
What other outreach activities should we consider now?
The most responsible course of action is to postpone your in-person outreach until it is safe to conduct it.  In-person outreach is very effective.  Get the funding agency's approval.

An alternative is to create asynchronous outreach content.  This is less effective, but can reach a wider audience.  For example, you can record YouTube videos of activities.  Disadvantages include difficulty getting your intended audience to watch the video.  Advantages over Zoom/synchronous include no need to schedule or register people, and the potential to do things over when they don't work.

Some people are running online competitions, but I don't know yet if they work.