I love the way that this site have given Bill Hicks and uncredited writing "credit" for this - seems like they know the score and have bigger testicles than I ever game them credit for - I wonder how many packs a day they smoke :-)
for those of you who don't know, before Leary became a corporate sell out and did beer commercials, he lifted his style, delivery, and most of his material (often verbatim) from a fellow comedian called Bill Hicks.
He does it quite well though and No Cure for Cancer is worth a chuckle, and its easy to see why Leary's watered down, corporately acceptable, and mass marketable versions of Hicks' style and material earned Leary the success that it did - the same success and recognition that eluded Hicks during his lifetime.
If you want your ranting and non-conformist comedy of a ultimately non challenging variety then Leary will probably do for you.
Otherwise I suggest you try the originator of Leary's work first