Well, okay, no. Not sing, as such, but rather do something aside from what I'm used to doing.
The other day I took my tauren warrior into ICC 10 as DPS. I got some compliments for my DPS which was nice, but more importantly, I didn't tank anything at all. Frankly, I've been a dedicated tank since the end of Ulduar, and while I still love tanking it's ever so nice to get a break from it every once in a while. This is probably the reason I'm still keeping my shamans current, as going to the occasional run as a healer pushes me out of my melee comfort zone. It's nice to get to see fights from a different perspective even if it's only occasionally.
Similarly, I'm a notorious achievement hater and yet, when people ask me if I'll help them get the things I usually don't refuse. Partially it's just to be nice, but also I kind of like seeing my achievement score go up without actually working at it: every achievement I get is a happy accident, complete with surprise foosh and a brief announcement.
So how about you? Do you ever stray out of your comfort zones?