Use the adjective convivial to describe your friend who is "the life of the party."
The Latin word convivium means "a feast," and when convivial was first coined in the 1660s, its meaning related to the excess of food and drink during such celebrations. You can also see convivial in convivere, meaning "to carouse together." Just when it seemed all convivial could ever do was describe people who overindulge, a new shade of meaning emerged: loving to be around people. After all, a big part of feasting is being with people you care about.