A number of times I have received SMS's from Optus (an Australian Telecommunications provider) on my pre-paid mobile phone at unacceptable times of the day/night.

The most recent was just before 2am on Friday the 21st of November 2008 (taken me a while to find somewhere to complain!) which had the text something like:

"For a limited time only, get 2 always win prizes for the price of 1 when you recharge online with a credit card for $30 or more, 2 unsub sms 'went' to 2222"

- From Optus MSG

which woke me up, I had to go to work the next day and it really annoyed the hell out of me!