When the app store first launched I would go searching for weird things, as time went on the amount of weirdness I would come across has gone way down. That's part of why I started the blog, to get some of that back.
YYZ is what I called my unfinished, unreleased Z-machine implementation. I was thinking about using it in an iOS app, so I wrote it in Objective-C, though I found that language wasn't a big improvement over C. I did get it far enough to start running Zork I, but I didn't implement saving and loading yet.
I noticed that some of the many Z-machine interpreters were named after magic words appearing in Zork, and I like Rush, so I picked a word that was reminiscent of "xyzzy".
I really loved upgrade soul! Haven't tried any others yet. Since you asked for suggestions, my shameless plug: the (gr)album app has some explorations of app-as-medium by musicians and visual artists http://gralbumcollective.com/ hit me up if you want a promo code for The Book of Sarth, the rest are free.
Quite an interesting list! Some of them are so absurdly specific it just cracked me up. It's insane how obsessed we are with our phones and connecting them to our daily lives at every moment. Hell, there's even apps for when we sleep!