I've read a couple of threads on this, probably at plantedtank.net, as Jason says, and thought that the concept sounded cool, because I like technology and programming, but then I remind myself that it doesn't really make sense to automate something if the process of automation takes more time than actually doing the something.
I have the same problem with my computer and various programs. Does it make sense to write a macro just because it's cool? Maybe.
So, if you figure out something cool to do with an arduino or raspberry pi, let me know and I'll copy it!