This might not work for you and your situation…
But I had this problem when I worked in corporate America. I finally decided to stop begging for work and found my own.
I began helping every department I could. I created strategic messaging for products, services and new initiatives. I was in HR, but helped product marketing, corporate communications, employee groups, the customer service team and the company university.
I even got a patent with a friend while I waited.
There are always others who need help with the services you offer. I suggest you find those teams and people. This not only keeps you sane from boredom while you wait patiently for your boss, but it also helps you network in case your boss goes down.
Plus, you will be energized when you finally do get a new assignment from your boss. Instead of doing the work with a head full of resentment… you can do it with pleasure because you won’t be angry at your boss.
In my case, all the extra work helped me see I could be a strategic communicator on my own… without the security blanket of a big company