The only thing you've got to look out for is that the quality of freeware text adventures (sorry, interactive fiction) is simply phenomenal. "Tangle (Spider and Web)" is a simply outstanding piece of craft with some of the finest puzzle based IF work I have ever seen. And that is one game amongst donzens of top quality stuff.
Originally Posted by GfK
On the other hand the IF community is small and does not promote itself all that well to outsiders so a well produced text-adventure that was properly promoted could into a wider desire for the games that is not being reached.
You need to check out the top-rated stuff on Baf's Guide and peruse Brass Lantern and the interactive-fiction newsgroups to see what is currently considered state of the art.
EDIT: Incidentally the IF community have (with their extensive experiance of natural language parsing) does some pretty funky stuff with Inform 7, one of the standard languages they use, the following sample is how you define an enumerated type and apply it to an object that is also defined.
Personally, I think that's super neat.
Colour is a kind of value. The colours are red, blue and green.
A block is a kind of thing. A block has a colour. A block is usually blue.
Before printing the name of a block: say "[colour] ". Before printing the
plural name of a block: say "[colour] ". Understand the colour property
as describing a block.