When your work speaks for itself, don't interrupt.
-- Henry J. Kaiser

You must include all income you receive in the form of money, property
and services if it is not specifically exempt. Report property (goods)
and services at their fair market values. Examples include income from
bartering or swapping transactions, side commissions, kickbacks, rent
paid in services, illegal activities (such as stealing, drugs, etc.),
cash skimming by proprietors and tradesmen, "moonlighting" services,
gambling, prizes and awards. Not reporting such income can lead to
prosecution for perjury and fraud.
-- Excerpt from Taxachussetts income tax forms