<p>In the future, take the person who puked's wallet and keep some form of their ID until they pay for the damage. Write them a note and stick it in their pocket telling them what they did, what they owe, and how they can get their ID back after they have paid for the vandalism. </p>
<p>In the meantime, make whomever invited the person over clean up the mess, or depending on time, call a carpet cleaning place and have them come clean up, and make sure you get a few copies of the bill so you can make sure that the puker or the roommate who invited them over pays for it.</p>