For folks without ADHD, you should know that stimulants, like Ritalin and Adderall, do not usually cause the same response as in non-ADHD people. I've spoken with many people on stimulants, and none of them enjoy taking the medication, beyond what it has done to improve their lives. Furthermore, most ADHD people develop tolerance to medication over long periods of time -- eventually the drug does little-to-nothing itself. For myself, taking even high doses of a Adderall regularly produces no result -- might as well be taking sugar pills. I have to take them periodically (a few times a week at most) to get any sort of benefit.
The proper medication and dosage should not make you feel "high" -- if anything it's almost the opposite. You get some clarity, an ability to direct your focus without a thousand distractions a minute, and perhaps even a sense of time.
I let some non-ADHD friends try a low dose of Ritalin when I had switched off of it and had some left over, and they were bouncing off the fucking walls -- I would strongly not recommend taking stimulants unless medically necessary.
For people with ADHD, they can be truly life saving. For recreational use, avoid.