(define factorial(lambda (n)(if (= n 0) 1(* n (factorial (- n 1))))))
Arguably the trailing parentheses are an eye chard.
With the download of Racket you also get DrRacket, which is an updated version of DrScheme, a learning tool aimed at programmers of different experience levels (and to my understanding different ages as well)
I've just begun to experiment with DrRacket to see what it can do. To get familiar with the Scheme style, I've been working through Teach Yourself Scheme in Fixnum Days.