A Restricted Stock Award, unlike a stock option (exercisable at some point in the future), gives the recipient shares of your startup’s Common Stock immediately for either cash or other consideration (such as services to be rendered).
Shares of Common Stock obtained under a Restricted Stock Award are often subject to a lapsing forfeiture restriction (or repurchase right by the startup if those shares were purchased for cash). This means that part or all of the shares may be repurchased by the startup if the recipient fails to provide the agreed-upon services or meet other commitments. The forfeiture restrictions of a Restricted Stock Award perform very much like vesting does with respect to stock options. Like typical vesting terms, forfeiture restrictions tend to lapse over a four-year period – with 25% of the shares fully owned by the recipient on the one-year anniversary of his or her start date at your startup, and an additional 1/48th of the shares owned outright each month over the subsequent three years.