"Prohibition-era gangster Al Capone contended, 'The government can't collect legal taxes from illegal money,' but he was wrong and wound up with eight years in prison for tax evasion," reports MSN Money. As tax time comes back around, the IRS would like to remind you that ill-gotten gains are taxable:
Illegal income. Illegal income, such as money from dealing illegal drugs, must be included in your income on Form 1040, line 21, or on Schedule C or Schedule C-EZ (Form 1040) if from your self-employment activity.
Kickbacks. You must include kickbacks, side commissions, push money or similar payments you receive in your income on Form 1040, line 21, or on Schedule C or Schedule C-EZ (Form 1040), if from your self-employment activity.
Stolen property. If you steal property, you must report its fair market value in your income in the year you steal it unless, in the same year, you return it to its rightful owner.
Found property. If you find and keep property that does not belong to you that has been lost or abandoned (treasure-trove), it is taxable to you at its fair market value in the first year it is your undisputed possession.
Gambling winnings. You must include your gambling winnings on Form 1040, line 21. If you itemize your deductions on Schedule A (Form 1040), you can deduct gambling losses you had during the year, but only up to the amount of your winnings.
Read about other "other income" here.