Reaction times can do amazing things when you get clever.
Relatively simple reaction times are reported to correlate g somewhere around 0.3 to 0.5 depending on details, with faster times associated with higher IQ. Brutally simple procedure: hold a ruler up vertically and have it dropped by an unpredictable process while holding fingers in a position to pinch it and stop the fall after you detect that it has begun to fall. Record how many centimeters it falls in a spreadsheet. If the number gets big, something is probably going wrong with your brain.
Having a friend on hand to drop the ruler is a big help. Also, for any drinkers out there, try this while sober and then after having some drinks (tested one at a time, because you'll be surprised how quickly results show up).
My friend and I are starting the Uberman sleep schedule (six 20-minute naps spread evenly throughout each day) tonight. Have other lesswrongians experimented with alternate sleep schedules? Are any of you qualified medical experts who can give input or advice? Success stories and failure stories would both be appreciated, and I'll keep you guys posted on our progress.