I was on a conference call recently and one-third of the folks showed up late. The reason I was on time, my brain remembers everything (NOT!).
I use a software program called Cool Timer. It is a free download that you can run on your computer when you need a timer, alarm clock, or stopwatch. I mainly use the timer feature which does a countdown in the background and then pops up a message when the timer reaches zero. It has saved me many times. Check it out!