Here is an example of spinning progress bars and whirleygigs. They may not work on every terminal and there are certainly nicer solutions, but if all you need is an indicator telling the user "I'm alive and still doin' stuff!", it might be good enough. Otherwise, cleen's suggestion may be what you want.

Of course, doing a percentage report would require initial knowledge of the amount of 'stuff' to be done. In some situations, this is easy to ascertain. In others, it's impossible and a spinner-type solution is the best way to go.