For those of you who know what Ubiquity is, I'll keep this brief. For the non-initiated, take a second to read about what many describe as Quicksilver for Firefox: http://labs.mozilla.com/2008/08/introducing-ubiquity/
You can install it here, read the tutorial and then come back when up to speed.
Cool stuff, right? So I took a look at their wiki earlier and was kind of surprised to find that nothing was listed there for Ruby...but you could search for php functions? Blasphemy...so I took their code and hacked it up a bit:
Easiest way to play with this in my opinion is, once you've installed Ubiquity, test it at chrome://ubiquity/content/editor.html
As you can see from the gist, its pretty easy to create a new command to play with and you can easily add in search capability for your favorite site. If its well known there's a shot someone's done that already.
Anyway, I thought this was pretty cool and imagine over time it will enable some pretty interesting mashups. Its almost a more powerful and approachable version of Yahoo Pipes, albeit a different sort of beast.