I did the little Crab music quest in Hechey Track and hit level 6. I know I hit level 6 because I'm level 6 now (duh) but I got the following text in my chat log:
Woo! you've reached level 6!!!
What I didn't see, however, is the usual whiz-bang celebratory stuff that usually happens when you level. I dunno if this was an event that simply didn't fire or maybe I clicked on something so ridiculously fast that I closed the window before my eyeballs sent the images to my neurons. If the latter is really the case, I guess I feel a little better about being superhuman and not getting my level 6 celebration message.