hubot-eavesdrop 
A hubot script to have your bot respond to specified keywords.
See src/eavesdrop.coffee for full documentation.
Installation
In hubot project repo, run:
npm install hubot-eavesdrop --save
Then add hubot-eavesdrop to your external-scripts.json:
Sample Interaction
user1>> hubot when you hear slow clap respond with http://i.imgur.com/0mKXcg1.gif
user1>> slow clap
hubot>> http://i.imgur.com/0mKXcg1.gif
user1>> hubot stop listening for slow clap
hubot>> Okay, I will ignore slow clap.
Also supports regular expressions.
user1>> hubot when you hear slow\s?clap(ping)? respond with http://i.imgur.com/0mKXcg1.gif
user1>> slow clapping
hubot>> http://i.imgur.com/0mKXcg1.gif
user1>> slowclap
hubot>> http://i.imgur.com/0mKXcg1.gif
Multiple responses can be specified for a single keyword.
user1>> hubot when you hear slow clap respond with 1|congrats!; 2|http://i.imgur.com/0mKXcg1.gif
user1>> slow clap
hubot>> congrats!
hubot>> http://i.imgur.com/0mKXcg1.gif
To reduce channel noise, keywords only trigger events once every thirty seconds.
The length of this delay can be changed by setting a HUBOT_EAVESDROP_DELAY environment variable.