I dyed mine blue once. It was one of those temporary rinses for black hair, that was supposed to give subtle blue highlights and rinse out after 6 washes. It turned my blonde hair a nice dark blue and lasted 6 months, going from dark blue to purple, to ash grey!

I got bored with the (real) grey a few weeks ago and went for a temporary red rinse. My aunt and cousin have bright red hair, my mother also had quite a lot of red. Mine originally had lots of red in it, but enough blonde so it didn't look red. The red rinse doesn't look too out of place but I must remember not to wear the purple top....

LTS