There's something kinda cool about creating games on platforms that weren't meant for game creation; it presents a whole set of programmatic challenges that leads one to come up with creative solutions to otherwise simple scenarios in typical gaming SDKs. It's kind of a brain-teaser as it goes beyond typical business application programming (generally boring, tedious, repetitive, and not fun) and forces one to think about more...challenging and creative programming tasks.
So I found it quite awesome that someone actually took this idea to another level and wrote PacMan...for Excel!.
My Tetris implementation is actually kind of similar in concept as it also utilizes the same basic technique of switching "cell"--in my case, list items--background colors to simulate pixels. I actually have a more complete version somewhere on my machine, but I have no idea where it's buried :-S.