Yes, the same one, multiple times. My "writing" icon.
Happened to me too. Was an amusing Gargoyles icon. Then it just went back to normal.
It's a guy I've never seen before...not a clue where it came from!
I must say I'm not too impressed with LJ so far. As Douglas Adams said of Vogon ships, the site looks "not so much designed as congealed." Based on the aphorism "how you do anything is how you do everything," although I have not seen the effect you describe, I would expect the site to have quite a few, long-standing, unpredictable bugs.