43things has a positive attitude. It looks good. It is fast. It is there to help you realize dreams. Popcorn, they even have functionality available as a webservice!
Although visually it is too busy (what’s the word?) if you first visit it.
I’ve found out it is written using Ruby on Rails. Since this is at least the third good Rails site I’ve encountered, I’ve had our Repro print a tutorial for further investigation.