Anyone know how to prevent a program from showing up in the taskbar, but still remain active (not minimised)?

I'll explain: I got one of those Dilbert daily calendar things that sit on the desktop. It has a small function bar, which I can click to expand a full calendar. The problem is that I don't like the taskbar to show the program running, and everything I have found to hide a task forces the program to run minimised, and that removes the function bar.