Missing Christina's Widgetopia, I've decided to dump my screenshots of examples of user interface and interaction into a flickr group rather than keeping in the vacuum of my own experience. So now you can view screenshots I'm grabbing at the Design Pattern flickr group and feel free to add your own. The example below is from Daylife.

Design patterns are generally repeatable solutions to a commonly occurring problems.

This group was created to post examples of web design solutions seen in the wild to help people compare different solutions, and to find existing and emerging patterns to design problems.

Tagging consistency will certainly help make this useful, but it is likely that people will use different tags to describe problems, e.g. will you use "sign in", "log in", or "login" to tag a sign in interface? Consistency will allow you do things like search for stuff like Design Patterns: clustering.