MY DUMBEST investment was to buy shares of Rambus at its all-time high on margin, due to an early-morning phone call to my house from a high-pressure "financial adviser" from my full-service brokerage. He told me that a court decision was ready to be announced and that this baby was set to pop! I was so clueless that I gave him the green light, only to see the stock plummet that very same day. I became pretty mad and woke up to the fact that I needed to take the reins of my financial future. I closed my account and stayed out of the game until I learned more. It was a hard lesson, but a valuable one.