Amusing bits from IRS Publication 525, Taxable and Nontaxable Income, Other Income:
Bribes. If you receive a bribe, include it in your income.
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.
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.
For all those honest criminals out there. ;)
(via Jacqueline)