Invented in 1953 by a local musician, the Denver Boot--that bulky device that clamps onto the wheel of a car and renders it undriveable--has been the scourge of parking scofflaws around the world ever since. Thanks to advances in technology, however, its reputation has become a little less fierce in Denver. The city introduced a "smartboot" last month that allows parking violators to free their booted cars by simply calling a 24-hour number to pay off outstanding fines with a credit card, debit card or check. Upon payment, the call center provides the caller with a release code. Vehicle owners must then return the boot to a designated drop-off site within the next 24 hours or face a $25 daily late-return fee, up to a maximum of $500. Last year, Denver booted more than 5,500 cars and generated about $1.4 million in paid tickets and fees. The SmartBoot device is produced by PayLock Systems Inc. To learn more, click here.