Nepetalactone, the 'active' ingredient in catnip, has been reported to show some behavioral effects when ingested by humans (or toddlers). Apparently it's raison d'etre is insecticidal and it does show some activity in repelling cockroaches. According to this article it was commonly used as a substitute for recreational marijuana in the 1960's, and people would even buy cat toys in order to 'score'. If you find that funny, check out some of the forums where people discuss the possibilities of getting high from catnip. My favorite quote,"my cat dosent smoke my bud so im not smoking his."
Anyways the CLEAR winner of this post is a link I ran into on boingboing about purifying kitty krack. This is a serious method for those who find that street catnip just isn't as pure as it used to be and involves some steam distillation. Also be sure to check out this video of totally baked cats. If your cat just isn't into it, don't worry it's probably not because it's a 'square cat'. It may still be hip to the scene but just non-responsive. Response to catnip is an autosomal dominant inherited trait.
Also thought I would mention a random link I ran into recently. The International Emetophobia Society website. That is a website for those with a fear of vomiting be sure to donate to those poor suffering people.