I have a HP Pavillion dv6t-3000 CTO (Online Customized), specs are:
Core i5-520m, 2.4GHz
ATI HD 5650
Anyways, whenever I play a demanding game the CPU gets to 103-105C, the GPU to over 98C.
I took it apart once and I see both share a rather small heat sink, there is absolutely no dust at all.
Yesterday, while playing Crysis 2 the laptop actually shut itself off due to the temps.
Originally the laptop would not overheat so much, when I just got it it maxed out at around 92C, which while still hot, is no where near as dangerous as 100+.
The only noticeable difference is the fan doesn't seem to spin up as quick as it used to.