I could just use a diversion and play chess or something, but I know in the back of my mind, I have to get back to that code sometime, so.. why not now?
For what it's worth, I had a burnout problem last year. I put in way too much time at work and it caught up with me. I took some time off and pretty much avoided touching computers. After the "so why not now" period, I actually started to enjoy being disconnected from my work. Then I started to miss working on the computer. Once I got to the point where I missed working, I knew I was ready to step back in. I just had to shake off the more recent bad associations with working and remember why I started working with computers in the first place. That re-energized me. The total process took about two weeks to get over a six month build-up/burnout.
I'll admit that I was lucky to have a manager who saw the problem and gave me some flexibility in ducking out of work for a few weeks and others may not be so fortunate. My only real advice is if you can put off that feeling of "why not now" and wait until you're exicted to get back to that code, then do it. It's hard to feel excited about something when you have to do it more than you want to.