have wondered how people stay motivated if Perl isn't their job?

For me that's an easy question to answer. It is the same way I stay motivated to mess about in C, Java, HTML, JavaScript, C++ and assembler. Sometimes all at once in a single day.

For instance: one of my pastimes is hacking around with microcontrollers. Mostly Z80s, Basic Stamps, PICs of various types, and the 8051 family. To that end I am messing around with writing a plugin for Eclipse to provide IDE services for SDCC just because I can. If I like my end product (if there is ever an end product) I may even make a Source Forge project out of it and let other folks join me in my fun.

I also have a very active imagination and for that reason can always think up a new project to work on and therefore I'm never bored. Some of my projects (a lot of my projects) are totally impractical and a complete waste of time. At least on the surface. If you can learn something while tinkering around, even better.

One of my long-term projects is to build my own brewery. That one project has spawned off dozens of sub-projects for all kinds of gadgets incorporating mechanical skills, electronics skills, woodworking skills (I suck at that) and most importantly my programming skills.

It's easy for me to stay motivated.