One of the best attempts was a really nasty little trick, basically a human-backed chatbot. The way it worked was like this:
You get an icq (at the time) client and proxy it through the bot, the bot goes and makes random friends.
When someone reponds to the bots 'opening' line (Hi how are you?) you get back a response. You now answer with two things at once, the first a regexp that matches the response and puts in wildcards for linguistic fluff, and the actual answer.
The bot stores both in its database, and passes the answer to the user. Who then replies.
Meanwhile the bot continues to find new 'victims', and everytime it gets back an answer it tries to make a match based on it's canned responses. It knows where in the conversation it is (context), so a response will only be matched in the right spot in a conversation.
After being the bots 'backend' for a couple of days it could keep up a conversation for a good 20 minutes from the 'hi how are you' until it would run out of steam, by using wildcards in a smart way it is amazing how 'relevant' an answer can be even though the match is only on one or two words.
It was some of the most fun I ever had with computers, not because it 'fooled' the users, simply because of seeing all these patterns in language.
You could probably re-implement the basics using a webform and some ajax in a couple of hours.
The hardest part was to figure out how to get on the ICQ network, someone was friendly enough to write micq and it was easy enough to splice the proxy bit in there.
The real challenge in making a chatbot is writing one that comes up with original stuff, this one just basically regurgitated whatever it was told on an earlier occasion.
edit: I've found the code, if you are really interested drop me an email and I'll send it to you, warning this is very ugly code, it was spliced together in a very short time from a bunch of stuff and it should really never see the light of day again. Frankenstein looks pretty in comparison :) It will also almost certainly not work (if you can find the micq it wants that might help, not sure if that is even working), fry your computer and so on...
Here is a small sample of what you could do with it (an attempt at getting people to visit camarades.com:
(I used a different domain to be able to track who actually visited the site), this the 'ruleset' after a couple of sessions.
color off
# info 12089101
rand 1
awaittarget 60 servertimeout
msg $target/Hi There !, I'm Jacques\nDo you like webcams ?
await 300 abort
!sleep 10
match explainfree (free free? cost?)
match explainrand how find
match languageno no do speak
match apologise (remove | fuck | go away)
match apologise fuck
match apologise go away
macro affirmative (cool | yes | yeah | yeh | yep | yup | da | si | sure | I do | very | like much)
match payload $affirmative
match explain need
match explaincam what
match maybe (dont know | maybe | could be)
match pity (no | nope)
match pity nope
match explain don't have
q
explainfree:
msg $target/Sure it's free !
await 300 abort
!sleep 10
match languageno no do speak
match apologise remove
match apologise fuck
match apologise go away
match payload $affirmative
match explain need
match explaincam what
match maybe dont know
match maybe maybe
match maybe could be
match pity no
match pity nope
q
apologise:
msg $target/Ok, sorry to disturb you, goodbye !
!sleep 10
q
explainrand:
msg $target/I found you through Linux/micq random people finder. So do you like cams ?
await 300 abort
!sleep 10
match apologise remove
match apologise fuck
match apologise go away
match payload cool
match payload yes
match payload yea
match payload yeah
match payload yeh
match payload yep
match payload sure
match payload I do
match payload very
match payload like much
match explain need
match maybe dont know
match maybe maybe
match maybe could be
match pity no
match pity nope
q
explaincam:
msg $target/A webcam is a camera connected to the internet
await 300 abort
match apologise remove
match apologise fuck
match apologise go away
match payload cool
match payload yes
match payload yea
match payload yeah
match payload yeh
match payload yep
match payload sure
match payload I do
match payload very
match payload like much
match explain need
match maybe dont know
match maybe maybe
match maybe could be
match pity no
match pity nope
q
apologise:
msg $target/Ok, sorry to disturb you, goodbye !
!sleep 10
q
payload:
url $target http://www.camerades.com/ Great !\nYou can see me *live*\non www.camerades.com\nEnjoy !\nThere are 100's of live cameras there and free software too !
!sleep 10
abort:
q
maybe:
msg $target/Hm, if you want to try check out www.camerades.com\nEnjoy !\nThere are 100's of live cameras there
!sleep 10
abort:
q
pity:
url $target http://www.camerades.com/ That's a pity, You can see\nme *live* on www.camerades.com\nThere are 100's of live cameras there\nAnyway, sorry to disturb you...\nGoodbye
await 180 abort
match describe what see
match explain what
match explain need
!sleep 10
abort:
q
languageno:
msg $target/No, I don't.\nThat's a pity, You can see\nme *live* on www.camerades.com\nThere are 100's of live cameras there\nAnyway, sorry to disturb you...\nGoodbye
await 300 abort
match describe what see
match explain what
match explain need
!sleep 10
abort:
q
explain:
msg $target/You don't need any software, or camera just a browser is enough.\n
!sleep 10
q
describe:
msg $target/Lot's of people and out door views from all over the world\n
!sleep 10
q
servertimeout:
!echo no response !
q- AIML engine
- MegaHAL engine
- proper parsers (most of them are written in lisp-like languages for some reason)
Now it really depends on what you want to do - only waste someone else's time? MegaHAL will do just fine. You can feed it conversations all the time and it will learn to interact in some environment rather quickly.
If you want some basic scripting, you should look at AIML-based soft. You can write your scripts and basic expression reduction in XML. There's a "javascript" tag in the specification, but noone really supports it. I map it to python functions in my bot and it works quite well. You will never parse more exotic sentences though - just basics. And your bot will not learn automatically.
If you want to use it for something really useful, look at the http://www.generation5.org/ articles. You'll find a lot of code that's easy to port to your favourite language there. Serious language parsers connected to something like word-net are the only way to go if you want good quality. And you need to create a lot of stuff yourself - afaik there are no standard response libraries like alice, because the parse format is not really standardised.
Lieutenant: What's our mission, captain?
Fake Kirk: Our five year mission: to seek out
new worlds and new civilizations.
To go boldly where no man has gone before.
Lieutenant: Did you not originally split the infinitive?
Fake Kirk: No. We beamed it out into open space,
Lieutenant. Widest possible dispersion.
Lieutenant: But didn't that kill it completely?
Fake Kirk: How?
Lieutenant: By ensuring it could never come back.
Fake Kirk: Explain.
Lieutenant: On widest possible dispersion you could
never re-integrate the original confinement
beam.
Fake Kirk: To read minds?
Lieutenant: Oh dear.
Fake Kirk: Lieutenant.
Lieutenant: Yes captain?
Fake Kirk: Lieutenant, get the doctor up here on
the double. How bad is it?
Lieutenant: It's not at all bad - just a flesh wound.
Fake Kirk: Oh, yes, it is. It's exactly the same.
Only this one works.