One day I was bored and picked some catnip (about an ounce with stems and leaves and everything fresh from a catnip plant in my backyard). Then I smashed the catnip into a coffee mug in no special way. Once the water was done boiling, I added it to the catnip in the mug, then covered the mug and let it sit for 10 minutes. After 10 minutes I pulled the catnip plant out of the water with tongs. The newly made tea was a shade of murky lime green.
So then I drank the tea at first sipping, then gulping.
+1 minute: It felt like the hot tea was spreading all around my body, not just to my stomach.
+5 minutes: There was a mild body relaxation feeling happening. My body also felt warm. No physcological effects or imparement.
+7 minutes: The relaxed body feeling was slightly increasing. Breathing in seemed a little easier. When breathing in, it felt like I was getting more energy and oxygen than normal. It was similar to the feeling of taking a deep breath after riding an amazing roller coaster, but not as strong.
+10 minutes: The effects have reached their peaks and are starting to fade away.
+20 minutes: Back to normal and it feels like I just took an amazing shower in a waterfall.
Overall, all I experienced was a mild body buzz for a short time. There were no effects similar to normal drugs, instead it was more like taking a vitamin or a health drink. For being bored and wanting to pass the time, it was worth it. If you want to get a good buzz, I wouldn't recommend catnip, because the effects are minimal. If you have nothing to do and are at grandma's house, go for it.