I used to love cool beans man! (we always added man)
Totally Rad
Buz Wrecker!
defenestrate - just a word, but such a great one, that can be used in lots of phrases, such as- "You better be nice to me, or I'll defenestrate you!" (I would never actually defenestrate anyone, but it's fun to say.)
Out gallivanting around - as in "You didn't get home by curfew last night because you were out gallivanting around!" (My dad used to use this all the time on me in h.s. I didn't know what it meant the first time, but I got the gist...now he denies saying it, but since he said it to me constantly from 16-18yrs old, my mom backs me up!)