I am looking for some Esperanto text, which is in the public domain or under a creative commons license.

I want to make some learning material out of it. I checked out Project Gutenberg, but unfortunately the books there are too complex and not very current.

Any ideas?

All material at the Esperanto Wikisource is available under a free license. That's the only other obvious candidate for free-licensed-only content. However, most of the material there is somewhat dated as well - might take a bit of digging around to find something appropriate for your purposes.

Alkanadi, if you go to the Tekstaro website you will find to the left of each source text a little symbol indicating whether the source is protected or unprotected. Most of them are unprotected.

Clicking on this symbol (for an unprotected source) gives you access to the whole of the source text to read onscreen.

I haven't tried it, but I would imagine that you can select as much or as little of the source text you require, copy the highlighted portion (control C on a PC) and dump it into a word processing programme (like Word).

Refer to the help notes (Klarigoj kaj helpo) for the procedure for gaining permission to use the text in your application.