syntax-let1

 ;; macro to bind a single variable 
 (define-syntax let1  
   (syntax-rules () 
     ((_ var expr body ...) 
      (let ((var expr)) body ...)))) 

Rather than

 (let ((foo (bar quux))) (frobnicate foo)) 

we get rid of a few parens and write:

 (let1 foo (bar quux) (frobnicate foo)) 

category-code