Some other amusing little hacks on Google App Engine.
I like LunchStr, for coordinating the office lunch expedition.
There are some slightly larger applications.
Most of the really complex stuff is still Google authored. Their directory is filling up fast, including some spam entries. They already have preferential attachment bias in their ranking.
Finally a complain! The user nicknames appearing all over these application are actually revealing people’s email addresses, just add @gmail.com. Feel free to star this defect complaining about how all these sweet little applications are revealing user-email addresses unnecessarily. (Did somebody say oauth?)