While I enjoy the official Lifehacker site, I find 43 folders to be even more informative and interesting, since it addresses all sorts of random little things. I'm currently enjoying the 43 folders wiki random unsorted hacks. My favorites?
The Forehead Ticket Trick: don't leave the driveway until everyone in the car puts her ticket on her forehead.
Buying a Diamond: if you can read printed material through the "diamond," it's not real
From the unsorted lifehacks (might not find again):
The Coin flip -- "If I can't make a quick decision about something that can be simplified into two outcomes, I designate them as head and tails, flip a coin, call it in the air, and then (here's the important part!) completely disregard the result -- I nearly always feel a quick flash of "c'mon, come up tails" as it lands, so I just go with that. The distraction of flipping a coin pierces the indecision. --sckot Vokes"
Dummy Cord -- "Something I used to do in the Army to ensure that I'd hold onto small and easily-lost items (flashlight, utility tool, etc.) when I was in the field was to literally tie them to my belt with nylon para cord. This obviously isn't going to be appropriate much of the time, but you'd be surprised how useful, and how reassuring, it can be. -- User: AdamGreenfield" [note: I use a carabiner for the same thing . . . keys always go on there, and I never lose them.]
Photocopies -- Blue highlighter doesn't show up on photocopies. -- GH 21 Mar 05
Easy shopping -- The least crowded time to shop at the cheap warehouse supermarkets during daylight hours is on Sunday, when church is in session. -- GH 21 Mar 05