Square is a startup that hopes to do nothing less than transform the way people pay for goods and services. The company was started by Twitter co-founder Jack Dorsey (who recently returned to Twitter while continuing to lead Square), someone obviously no stranger to disruptive technologies.

A tiny, cheap card reader, coupled with a smartphone, lets anyone take credit card payments: crafters, babysitters, food trucks, photographers, you name it. You no longer need an expensive cash register to do business, nor a bulky, expensive credit card terminal or even a merchant account with a bank. While you could do simple person-to-person payments with services like PayPal, most people are already comfortable using a credit card.

My partner Valentino Valdez and I used Square to sell Kukui High School merchandise at craft fairs, and while most craft fair shoppers carry cash, the ability to use a credit card inspired may to buy a lot more stuff than they normally would.

Today, Square launched the next phase of their campaign to replace the old-fashioned cash register, introducing both Square Register and Card Case. With all this renewed attention on Square, and given my own affection for the technology, I sat down with Burt Lum today to do a quick video about it.

(We're experimenting with a video series called "Techspotting," after posting a test episode last week that explained Namesake.)

I've talked about Square so much, the company recently sent me a T-shirt and a box of the devices to give away. So while you can always request one for free from the Square website, I'd also be happy to give you one if you want to try it out.

Even if you don't have a product or service to sell, I've found it's a great way to take care of those friends or coworkers who never seem to have cash when the time comes to split the lunch tab!