Probably the biggest so far (got it yesterday) was right after opening the box and having a play through.
I was just launching everything i could find, and while surfing i went back to the task switcher and had about 30 programs open.
Hadn't even noticed, since everything was still running smoothly.

The other was logging into my linux server and launching an X program, that's just so awesome.

Gonna have a lot of fun with this thing.