Curiosity normally kills the cat, but if the cat emulates the roadrunner, running with it becomes the norm!
Asking many questions and finding too little answers catapulted my entry into email. When I happened upon an email marketing project during a coworkers absence, I found there were no development standards, templates, libraries, or testing protocols in place for the program. My curiosity turned into real-time, make it work situations that lead to the creation of an archive of over 25 templates (for newsletters, eblasts, and beyond) and 10 plus libraries of mods that can function in any given template (Non-inline CSS styles compensate for all needs). They were not testing, so after already having trolled through so many Litmus articles for open source tips, it was my first choice for a testing platform. So, now my buy-in for design, standardizing code, and using a testing platform has created a manageable (dev & design) workflow for the email campaigns. And after you can create and manage a standard, then you can look beyond for more challenges.
This year my buy-ins are a little more focused: A code minimizer (to strip unused styles, spaces, and comments-without eliminating conditional statements) for Yahoo, Gmail, and Android clients rendering by character count (code name: Ugly Duckling), an easy to manage automation platform for populating links (before deploy) in the standard templates (If this sounds interesting: so far the structure uses Ruby and Javascipt combo to pull from a database already established for the .com and 'manages' files via snippets), and a more over all design focus.
But, there is so much you can buy-in for with email!