Comment Asterisk works for me. (Score 1) 107
I dial 252 (ALArm) from the device I want to be called at, and enter a time at the prompt. At the appointed time, the lovely voice of Allison Smith tells me it's my wake up call and presents me with a random 3-digit number to enter. If I don't answer, hang up, or get the number wrong, I'm called back every two minutes until I get it right. The random number business is necessary because sometimes, if I don't have to do a slightly complex task, I'll just hang up and go back to sleep.