I've written a number of bots which are chugging away on Twitter, and will respond to certain phrases. They are:
@for_a_dollar was the first bot, and is pretty basic. If you tweet the word "Robocop", you'll get a response with a quote from the movie. It's fun, and reveals several things, but mostly that a lot of people that talk about Robocop don't know anything about the movie.
@iaminigomontoya was next, and is based on The Princess Bride. If you tweet "Inconceivable!" (with the exclamation point - very important!), you'll get a classic response. I wanted this bot to be nominally more interactive. So, if you respond to that tweet, you'll get another response. This bot is probably the most popular. People seem to fall into two categories on this one. 99% of the people who trigger this bot know exactly why they got it, and they love it. The other 1% don't have a fucking clue, and without fail seem to be conservative douches. The bot basically got into an argument, summed up nicely here:

I was surprised when I saw that no one had made a beetlejuice bot, so @Betelgeuse_3 was born -- it needed to be done. If you tweet the word "beetlejuice" three times, you'll get a response. I can't believe no one had come up with this yet! My main discovery on this one is that a lot of people in Brazil hit this one for some reason.
@dr_rumack isn't a very busy bot -- it responds to the phrase "surely you must be joking" made famous in the movie 'Airplane'.
@initech_bill responds to a number of tweets related to Office Space -- this is probably my favorite bot of them all.
Finally, @mirror_magick responds to tweets that include the phrase "Mirror mirror on the wall..."
If you've stumbled upon this page because one of my bots is irritating you, just let me know and I'll stop it from happening. I only intended this to be fun, not spammish.