An attempted contract that is made for an illegal purpose or that is against public policy cannot be enforced by either party and is void. In contrast, a contract that is made by a minor (usually under age 18), or that is based on a mutual mistake, or that was made on the basis of a fraudulent misrepresentation by one party, is voidable and may be rejected by a party who was at a disadvantage when the contract was made. A voidable contract may also be ratified and accepted by such a party—after a child reaches the age of majority (usually 18), or the parties become aware of their mutual mistake, or a party learns of the other party’s misrepresentation and proceeds with performance of the contract.

In Colorado, a contract created for an illegal purpose or against public policy is considered void and unenforceable by law. This means that neither party can seek legal recourse to enforce the terms of such a contract. On the other hand, contracts involving minors (typically under the age of 18), those based on mutual mistakes, or those formed under fraudulent misrepresentation are categorized as voidable. Voidable contracts can be rejected or affirmed by the disadvantaged party. For instance, a minor has the right to disaffirm a contract before reaching the age of majority or within a reasonable time afterward, but they may also choose to ratify the contract upon reaching adulthood. Similarly, parties to a contract can either rescind or ratify the agreement upon discovering a mutual mistake or fraudulent misrepresentation. It's important to note that the specific circumstances and the nature of the contract can affect the legal remedies and actions available to the parties involved.