When you say interesting, you mean flashy crap that does nothing but hinder your experience at the cost of showing off?
Have you done anything with the DLL before? Yes, you can make useless things with it (aka "flashy crap"), but you can do the same with regular mIRC scripting. However, you can also make very useful features on scripts, such as an internal chat window in a game that looks and acts just like mIRC's main chat window. There are also a wide variety of features you can add to a script to make it more useful rather than just flashy, thereby increasing a user's experience rather than hindering it.