Net Asset Value
On September 10, 2008, I began treating my Margin Account like a hedge fund.  Actually, all I did was create a spreadsheet with a table showing the total value of the account divided by a round number of shares.  This creates individual shares, like a mutual fund, worth a specific fraction of the total fund, or Net Asset Value (NAV).  I did this to account for deposits and withdrawals from the fund.  Below is the NAV chart over time.
The recent volatility in the markets has provided opportunities for short-term trading, but also for adding to some losing positions as well.  The big dip during October was a result of me adding to some oversold stocks/ETFs I owned, and selling for profits on the rebound.
Overall, the NAV returned 24.2% on the month, on top of the 28% gained in September.