As soon as I saw this idea I was wrapped. I possibly would not have thought of this idea had I not already had a hint. Use Google Calendar as your longterm memory.

My brother's birthday was last month, and I bought him a digital camera. Not long after ordering it, I opened up GCal, went to my brother's birthday, and added this to the event description: "2007: Got him a digital camera. It cost $300." I do this for everyone now, for Christmas as well. Now when I wonder "Hmmm, what did I get/how much did I spend on Person X last year? Or the year before that? Or 4 years before that?" I can actually find out in seconds.

In addition to past important dates, it would be a good idea to Calendar this event for next year so that you do not forget the birthday when it comes around again.

ALSO, I have a good idea for my business, I can add past sales data (what customer x bought today) and calendarise to call the customer in 3 months time, six months time and on the anniversary of the sale. It helps me build to a sale already completed and enables me to seek new business on the anniversary of the original sale.

I CANNOT justify a full-fledged CRM for my little business. Google Calendar will just do fine for the time being.