If you want to build an online following based on this, I warn you that the market has already been cornered.
1. Live editing, where your code evals and applies to the running image as you write it in your editor.
2. Easy full-proof macros. Not to be confused with the text-wrangling style of macros you would find in C.
Why aren't features #1 and #2 more popular in other languages? People don't miss what they never experienced. And both of those features require design at the runtime level and syntax level of the language to be implemented in a way that doesn't suck. They can't just be bolted on to a any random language like C++. Even though C++ likes to bolt on every feature it can.
Why would you learn lisp? To get features #1 and #2 in hopes of increasing your productivity.
Seriously though, tinkering with Common Lisp did prepare me a bit for my first Rails job since Ruby is, as I describe it, like "Perl and Smalltalk had a baby with Lisp sitting in the closet dressed like Superman, watching". Pragmatically, you might not need to touch Lisp, but going through it may show you some common pitfalls that occur in other languages and makes you wish there were Lispy features outside of it.