The concept of time is constantly in flux. While some days seem to stretch on for-ev-er, some nights pass so quickly that we can't remember them at all. But maybe that has less to do with the time-space continuum and more to do with taking stiff pulls from our canteen. Either way, in bull-riding, life is broken down into eight-second increments. It's easy to mindlessly blow off that small snippet of time while staring at the vending machine, but eight seconds trying to stay on the back of a one-ton Brahma might as well be a lifetime. See for yourself as the Family Arena (2002 Arena Parkway, St. Charles; 636-896-4242 or www.familyarena.com) hosts the Longhorn World Championship Rodeo at 8 p.m. Friday and Saturday and 2 p.m. Sunday (January 12 through 14). In addition to bull-riding, the event also features bronc-riding, barrel-racing and roping all things that make you appreciate the value of a second (and an intact collarbone). Tickets for the rodeo cost $9 to $27 and are available through MetroTix (314-534-1111 or www.metrotix.com).