Speaking as a guy who is still waiting for the Ritalin to kick in today, if I can’t get into one of these clinical trials, I may just bang my head against a light socket until I get zapped. Electrical currents may induce flow state:

If your brain isn’t just naturally inclined toward the flow, though, there is the option of zapping it into line. This is called transcranial direct current stimulation—basically running a very small electric current through specific parts of the brain. In some studies, and for some tasks, it’s been shown to induce a feeling very much like a flow state, and possibly make it easier for people to get to a high level of skill faster.