Best investment for $5,000 for quick return(6-18 months)?

Need to know best investment for $5,0000 American. I am open to day trading currency, cash deposits, stocks, bonds, and commodities. Beleive I can get 6.5% on a cash deposit of $5,000 for 6 months. Have enough capitol to tie up $10,000 for a period of 2 years. Looking for largest returns for shortest periods. I am interested in both potential and garaunteed returns. Also interesred in high yeild mutual funds and hedge funds.