I am trying to learn at least one new programming language each year. Most programming languages are imperative, so this isn't very difficult if you are a bit experienced already, although I also had fun with several functional languages. This year, I tried out ActionScript/Flash, because it's quite popular today.

My review as C++ programmer: I noticed very soon that Flash/ActionScript really is a framework for creating animated banners for websites only. Everything else you can do with it is built around this banner-framework, so if you want to create something a bit more sophisticated, you'll struggle with lots of problems. The major problem is that ActionScript is simply slow. Try calling one single simple method in a nested for loop each frame and you'll get punished by a drop of framerate by about 90%.
The image on the left shows a program I tried to create, writing a simple iso engine in pure ActionScript. The engine simply renders scrollable iso tiles of a 100x100 map, and it is extremely slow. When I wrote something similar nearly 10 years ago using Delphi on my Pentium 60, the output rate was higher. The slowness doesn't have to do anything with the graphics, it's only the loop which calculates the tile positions. There are ways to improve this for example by inlining calls manually, but that's very exhausting and IMO should not be necessary anymore today.
But apart from this, Flash is quite a mighty framework, targeted at graphic designers.