One of the apps that I really like under Mac OSX is this app called Alfred. It is a powerful launcher that is very similar to QuickSilver. Having used both, I settled with Alfred for my personal preference.
Alfred is a free app but you can really extend the functionality by using PowerPack which you have to pay. I went ahead and got the powerpack and I never regretted it since. You can do custom searches, shell scripts, include Automator and Workflows into the app.
The link here provides some extensions that are extremely useful. So based on some of these extension scripts, I wrote my own extension to the app which I personally use a lot. It is a very simple nslookup tool that lets you do nslookups inside Alfred and posts the results in Growl. It also copies the output to your clipboard if you want to paste it. Here is some screenshots:
RESULTS FROM GROWL NOTIFICATION
There are bunch of extensions out there, and the above example just uses three lines of bash code.
You can download the Nslookup Utility here.