"Good Housekeeping" put together a list of the most popular terms for every year from 1926 to 2006. Most of the older ones are things like "baloney" and "snazzy." We'll start with the '60s . . .
2000, "whassup?" . . . 2001, "whale-tail," which is when your thong sticks out . . . 2002, "hella" . . . 2003, "peeps" . . . 2004, "muffin top" . . . 2005, "fo shizzle" and "fo sheezy" . . . and 2006, "sick." As in, "Dude, that shirt is so sick."