Tying a string around your finger is so 19th-century. These days, if you want to remember to do something, you get your phone to remind you.
Ah, but in my experience, most phones aren't very good at nagging. In fact, many don't even have alarm-capable task apps. Even Siri, which you can vocally instruct to "remind me to follow up with part supplier at 10 a.m. Monday," only issues its notices once. They're too easy to miss.
That's why I love, love, love the Web service Oh, Don't Forget. With it you can set up a simple reminder that gets delivered to your phone (or someone else's) as a text message, something I find a lot harder to overlook or ignore.
Using your browser, you simply enter your phone number, the desired delivery date and time, and the reminder you want sent. Then click Create and you're done.
For example, I'm headed out of town next week. There's one work-related task I need to perform while on vacation. Rather than jumping through the hoops of creating a new calendar entry, setting an alarm for it, and all that, I set up a text-message reminder in Oh, Don't Forget. It took about 10 seconds.
Similarly, I could create a reminder that goes to an employee or co-worker at a designated time. The service will transmit to whatever mobile number you enter; it doesn't have to be yours. (Granted, the potential for abuse here is huge. Be good, no pranks!)
I've been using ODF for several months, and it's always worked flawlessly. It's even smart enough to know what time zone my phone is in and schedule the reminder accordingly. (In other words, if I create a reminder for, say, 9 a.m., it won't send it at 6 a.m. if I'm three time zones over.)
The real beauty of Oh, Don't Forget? You don't have to sign up for anything, register for anything, confirm anything, or pay anything. Just three quick steps and you're done. It's free (though standard messaging rates apply), and blissfully easy to use.
That said, you might want to consider going "pro." Oh, Don't Forget Premium lets you set up recurring messages (kind of like an SMS-powered to-do list), review message logs, maintain an address book, and so on. It costs $4.95 per month or $47.50 annually.
Personally, I'm happy to use the free version for the occasional reminder. It works like a charm.