Hey guys, sorry I'm late. I think some of the above ideas have merit, but wanted to try and help with the free-flow of ideas.
1. You could use the main halyard and just swing across ala Tarzan style.
2. After making sure the sidedeck is clear, position yourself right near the stern. Have your friend motor at full power (Giv'er everything she's got Scotty), just before you reach the spot where the boat runs aground you start running forward (again at full speed), as you pass the shrouds yell out "NOW!" whence your friend puts the boat in neutral and slams on the brakes!!!! As you reach the bow pulpit, jump. Next thing you know, you are ashore. Repeat process for rest of crew.
3. (I like this one best) Let your friends go ashore, by whatever means they prearranged, tell them you will be along shortly. At this point you need to try and look busy. When they are well away from the boat and near shore, you slip the anchor and leave!!!!!! (Think Pirate!!) You become an instant legend, a boat owner, can change your name to something cool like "Golding Beard", and are rid of those dumb a#$ friends finally!