* [Oleg Kiselyov's Haskell lambda calculator](http://okmij.org/ftp/Computation/lambda-calc.html#lambda-calculator-haskell).
* The top-down JavaScript lexer and parser at <http://javascript.crockford.com/tdop/index.html>.
-Improvements we hope to add soon: the ability to reduce Combinatory Logic combinators and report the result as combinators, rather than in lambda forms.
+Improvements we hope to add:
+* detecting some common cases of non-normalizing terms (the problem of determining in general whether a term will normalize is undecidable)
+* returning results in combinator form (the evaluator already accepts combinators as input)
+* displaying reductions one step at a time
+* specifying the reduction order and depth
+* allow other binders such as ∀ and &exists; (though these aren't interpreted as doing anything other than binding variables)
+
+Other Lambda Evaluators/Calculutors
+-----------------------------------
+
+* [Peter Sestoft's Lambda calculus reduction workbench](http://www.itu.dk/people/sestoft/lamreduce/index.html) Very nice! Allows you to select different evaluation strategies, and shows stepwise reductions.
+* [Chris Barker's Lambda Tutorial](http://homepages.nyu.edu/~cb125/Lambda)
+* [Lambda Animator](http://thyer.name/lambda-animator/)
+* [Penn lambda calculator](http://www.ling.upenn.edu/lambda/) Pedagogical software developed by Lucas Champollion, Josh Tauberer and Maribel Romero. Linguistically oriented. Requires installing Java (Mac users will probably already have it installed).