I took CS193P when it was first offered in 2007; one of my favorite classes at Stanford because it was so hands-on. At the time few people had iPhones, so everyone in the class got a free iPod Touch for development. My final project was a photo sharing app with a Polaroid shake to reveal mechanic… lightly influenced Instagram which Kevin and I built a few years later!
IG co-founder here: users 1 and 2 were our first two attempts at creating users end to end when getting Instagram v0.1 hooked up to the backend we'd written. There was a bug so they were left in an incomplete state; post bugfix, 3 was my co-founder Kevin and 4 is me.