Wanted to give some brief input...there was one summer a couple years ago I sort of used caffeine pills for recreational purposes. I was low on money for weed at the time and I had just come off a 4-month stint trying out amphetamines for the first time in my life - I was pretty hooked to amps then, but, at the same time, I only used them for school-work, and I didn't give a fuck about them when summer rolled around.
Long story short, I used anywhere from 2-5 200 mg caffeine pills in the course of a day every other day or so that summer. I usually didn't do more than 2 max at one time to avoid much noticeable tension, but, still, I would usually do that 2-3 times a day, so it added up. I personally thought it was a pretty good buzz, actually. However, I don't know how much of that would be a placebo effect. I wasn't naive to stimulants due to my previous use of amps, so I knew it wasn't shit compared to amphetamines, but, nonetheless, I enjoyed the rushing feeling and slight euphoric uplift that caffeine pills provided. Then again, I was desperate for some sort of entheogen/substance intoxication, so take that for what it is.
The most enjoyable things for me to do while on caffeine pills were: listening to fast, loud, sometimes even obnoxious music; playing racing video games, like anything along the lines of Mario Kart 64, etc. etc.; also randomly just enjoyed surfing the web, but NOT watching the TV, which made me feel restless.
I also would take walks and sometimes work out when on caffeine pills, but I stopped doing either of those activities whilst on caffeine pills pretty quickly - no reason to make your heart beat faster when it's already artificially being forced to beat faster.
It was an experimental summer with caffeine pills produced out of my own boredom and pure want to do something - it's not like I regret it, but it was pretty fucking pointless all the same. They are cheap as shit though - however, if I was going to make an analogy between caffeine pills and weed, the caffeine pills are, in my opinion, way worse when compared to amphetamines than even when comparing most schwag to chronic grade weed. Caffeine pills are like the dirt in dirt schwag, real talk...