Common Lisp design patterns

Actually catalog of common Common Lisp idioms. Some idioms are generalizable for all major Lisp dialects. Another nice idea for ELS 2010.

reduce map
with-x
defx or def-x
dox or do-x
<conditional-operator>-let or b<conditional-operator> [b is for binding]
...

Provide examples from SISCOG code base?

Each pattern should have an associated implementation strategy for being defined with macros.